diff --git a/.travis.yml b/.travis.yml
index 5dae951cc..51c999050 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,13 +1,15 @@
 # configuration for https://travis-ci.org/dogecoin/libdohj
 sudo: false
+dist: bionic
 language: java
-jdk: oraclejdk8
-install:
-# before_install:
-  - sudo apt-get -qq update
-  - sudo apt-get install -y protobuf-compiler
+matrix:
+  include:
+  - jdk: openjdk8
+    env: GRADLE_VERSION=6.7.1
+  - jdk: openjdk11
+    env: GRADLE_VERSION=6.7.1
+install: true
+before_script:
+  - gradle wrapper --gradle-version=$GRADLE_VERSION
 script:
-  - gradle -q clean install
-  - jdk_switcher use openjdk7
-  - cd core
-  - gradle -q clean build
+  - ./gradlew clean build
diff --git a/build.gradle b/build.gradle
index 2043f8c88..74a59e7b0 100644
--- a/build.gradle
+++ b/build.gradle
@@ -1,6 +1,7 @@
 buildscript {
     repositories {
         jcenter()
+        mavenCentral()
     }
 
     dependencies {
diff --git a/core/build.gradle b/core/build.gradle
index 45b2e4c19..f9de088d0 100644
--- a/core/build.gradle
+++ b/core/build.gradle
@@ -1,40 +1,42 @@
-apply plugin: 'java'
+apply plugin: 'java-library'
 apply plugin: 'maven'
 
 version = '0.15-SNAPSHOT'
 archivesBaseName = 'libdohj-core'
 
 dependencies {
-    compile 'org.bitcoinj:bitcoinj-core:0.15.9'
-    compile 'com.madgag.spongycastle:core:1.58.0.0'
+    api 'org.bitcoinj:bitcoinj-core:0.15.10'
+    implementation 'com.madgag.spongycastle:core:1.58.0.0'
+    implementation 'com.google.guava:guava:30.0-android'
     implementation 'com.lambdaworks:scrypt:1.4.0'
-    implementation 'com.google.guava:guava:24.0-android'
-    compile 'com.google.protobuf:protobuf-java:3.5.1'
-    implementation 'com.squareup.okhttp3:okhttp:3.9.1'
-    implementation 'org.slf4j:slf4j-api:1.7.25'
+    implementation 'com.google.protobuf:protobuf-java:3.13.0'
+    implementation 'com.squareup.okhttp3:okhttp:3.12.12'
+    implementation 'org.slf4j:slf4j-api:1.7.30'
     implementation 'net.jcip:jcip-annotations:1.0'
     compileOnly 'org.fusesource.leveldbjni:leveldbjni-all:1.8'
-    testImplementation 'junit:junit:4.12'
-    testImplementation 'org.easymock:easymock:3.2'
+    testImplementation 'junit:junit:4.13.1'
     testImplementation 'com.fasterxml.jackson.core:jackson-databind:2.5.2'
-    testImplementation 'org.slf4j:slf4j-jdk14:1.7.25'
-    testImplementation 'com.h2database:h2:1.3.167'
+    testImplementation 'org.slf4j:slf4j-jdk14:1.7.30'
     testImplementation 'org.fusesource.leveldbjni:leveldbjni-all:1.8'
 }
 
-sourceCompatibility = 1.7
+sourceCompatibility = 1.8
 
 test {
     exclude 'org/libdohj/net/NetworkAbstractionTests*'
+    testLogging {
+        events "failed"
+        exceptionFormat "full"
+    }
 }
 
 task javadocJar(type: Jar, dependsOn: javadoc) {
-    classifier = 'javadoc'
+    archiveClassifier  = 'javadoc'
     from javadoc.destinationDir
 }
 
 task sourcesJar(type: Jar, dependsOn: classes) {
-    classifier = 'sources'
+    archiveClassifier  = 'sources'
     from sourceSets.main.allSource
 }
 
diff --git a/core/src/main/java/org/libdohj/params/LitecoinTestNet3Params.java b/core/src/main/java/org/libdohj/params/LitecoinTestNet3Params.java
index e80c18dac..7d5d1081c 100644
--- a/core/src/main/java/org/libdohj/params/LitecoinTestNet3Params.java
+++ b/core/src/main/java/org/libdohj/params/LitecoinTestNet3Params.java
@@ -18,7 +18,7 @@
 package org.libdohj.params;
 
 import org.bitcoinj.core.Utils;
-import org.spongycastle.util.encoders.Hex;
+import org.bouncycastle.util.encoders.Hex;
 
 import static com.google.common.base.Preconditions.checkState;
 import java.io.ByteArrayOutputStream;
diff --git a/core/src/test/java/org/bitcoinj/core/AltcoinBlockTest.java b/core/src/test/java/org/bitcoinj/core/AltcoinBlockTest.java
index 4aa525805..802238689 100644
--- a/core/src/test/java/org/bitcoinj/core/AltcoinBlockTest.java
+++ b/core/src/test/java/org/bitcoinj/core/AltcoinBlockTest.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2015 jrn.
+ * Copyright 2015, 2021 Ross Nicoll.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -15,21 +15,16 @@
  */
 package org.bitcoinj.core;
 
-import java.util.BitSet;
-
-import static org.junit.Assert.assertArrayEquals;
-import static org.junit.Assert.assertEquals;
 import org.junit.Before;
 import org.junit.Test;
-
 import org.libdohj.params.DogecoinMainNetParams;
 
-/**
- *
- * @author jrn
- */
+import java.util.BitSet;
+
+import static org.junit.Assert.assertEquals;
+
 public class AltcoinBlockTest {
-    private final NetworkParameters params = DogecoinMainNetParams.get();
+    private static final NetworkParameters params = DogecoinMainNetParams.get();
 
     @Before
     public void setUp() throws Exception {
diff --git a/core/src/test/java/org/bitcoinj/core/AuxPoWTest.java b/core/src/test/java/org/bitcoinj/core/AuxPoWTest.java
index 424055c7c..bdf49f977 100644
--- a/core/src/test/java/org/bitcoinj/core/AuxPoWTest.java
+++ b/core/src/test/java/org/bitcoinj/core/AuxPoWTest.java
@@ -1,20 +1,22 @@
 package org.bitcoinj.core;
 
-import java.math.BigInteger;
-import java.util.Arrays;
-import java.util.Collections;
-
+import org.junit.Before;
+import org.junit.Test;
 import org.libdohj.core.AltcoinSerializer;
 import org.libdohj.params.DogecoinMainNetParams;
 import org.libdohj.params.DogecoinTestNet3Params;
 
-import static org.bitcoinj.core.Util.getBytes;
-import static org.junit.Assert.*;
+import java.math.BigInteger;
+import java.util.Arrays;
+import java.util.Collections;
 
-import org.junit.Before;
-import org.junit.Rule;
-import org.junit.Test;
-import org.junit.rules.ExpectedException;
+import static org.bitcoinj.core.Util.getBytes;
+import static org.junit.Assert.assertArrayEquals;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertThrows;
+import static org.junit.Assert.assertTrue;
 
 /**
  * AuxPoW header parsing/serialization and validation
@@ -34,7 +36,7 @@ public void setUp() throws Exception {
     @Test
     public void parseAuxPoWHeader() throws Exception {
         byte[] auxpowAsBytes = getBytes(getClass().getResourceAsStream("auxpow_header.bin"));
-        AuxPoW auxpow = new AuxPoW(params, auxpowAsBytes, (ChildMessage) null, params.getDefaultSerializer());
+        AuxPoW auxpow = new AuxPoW(params, auxpowAsBytes, null, params.getDefaultSerializer());
         MerkleBranch branch = auxpow.getCoinbaseBranch();
         Sha256Hash expected = Sha256Hash.wrap("089b911f5e471c0e1800f3384281ebec5b372fbb6f358790a92747ade271ccdf");
 
@@ -54,11 +56,10 @@ public void parseAuxPoWHeader() throws Exception {
     @Test
     public void serializeAuxPoWHeader() throws Exception {
         byte[] auxpowAsBytes = getBytes(getClass().getResourceAsStream("auxpow_header.bin"));
-        AuxPoW auxpow = new AuxPoW(params, auxpowAsBytes, (ChildMessage) null, params.getDefaultSerializer());
-        byte[] expected = auxpowAsBytes;
+        AuxPoW auxpow = new AuxPoW(params, auxpowAsBytes, null, params.getDefaultSerializer());
         byte[] actual = auxpow.bitcoinSerialize();
 
-        assertArrayEquals(expected, actual);
+        assertArrayEquals(auxpowAsBytes, actual);
     }
 
     /**
@@ -67,9 +68,9 @@ public void serializeAuxPoWHeader() throws Exception {
     @Test
     public void checkAuxPoWHeader() throws Exception {
         byte[] auxpowAsBytes = getBytes(getClass().getResourceAsStream("auxpow_header.bin"));
-        AuxPoW auxpow = new AuxPoW(params, auxpowAsBytes, (ChildMessage) null, params.getDefaultSerializer());
+        AuxPoW auxpow = new AuxPoW(params, auxpowAsBytes, null, params.getDefaultSerializer());
         auxpow.checkProofOfWork(Sha256Hash.wrap("0c836b86991631d34a8a68054e2f62db919b39d1ee43c27ab3344d6aa82fa609"),
-            Utils.decodeCompactBits(0x1b06f8f0), true);
+                Utils.decodeCompactBits(0x1b06f8f0), true);
     }
 
     /**
@@ -87,13 +88,10 @@ public BigInteger getBlockDifficulty(Block block) {
             }
         };
         byte[] auxpowAsBytes = getBytes(getClass().getResourceAsStream("auxpow_header_no_tx_header.bin"));
-        AuxPoW auxpow = new AuxPoW(namecoinLikeParams, auxpowAsBytes, (ChildMessage) null, namecoinLikeParams.getDefaultSerializer());
+        AuxPoW auxpow = new AuxPoW(namecoinLikeParams, auxpowAsBytes, null, namecoinLikeParams.getDefaultSerializer());
         auxpow.checkProofOfWork(Sha256Hash.wrap("5fb89c3b18c27bc38d351d516177cbd3504c95ca0494cbbbbd52f2fb5f2ff1ec"),
-            Utils.decodeCompactBits(0x1b00b269), true);
+                Utils.decodeCompactBits(0x1b00b269), true);
     }
-    
-    @Rule
-    public ExpectedException expectedEx = ExpectedException.none();
 
     /**
      * Check that a non-generate AuxPoW transaction is rejected.
@@ -101,12 +99,12 @@ public BigInteger getBlockDifficulty(Block block) {
     @Test
     public void shouldRejectNonGenerateAuxPoW() throws Exception {
         final byte[] auxpowAsBytes = getBytes(getClass().getResourceAsStream("auxpow_header.bin"));
-        final AuxPoW auxpow = new AuxPoW(params, auxpowAsBytes, (ChildMessage) null, params.getDefaultSerializer());
+        final AuxPoW auxpow = new AuxPoW(params, auxpowAsBytes, null, params.getDefaultSerializer());
         auxpow.getCoinbaseBranch().setIndex(0x01);
-        expectedEx.expect(org.bitcoinj.core.VerificationException.class);
-        expectedEx.expectMessage("AuxPow is not a generate");
-        auxpow.checkProofOfWork(Sha256Hash.wrap("0c836b86991631d34a8a68054e2f62db919b39d1ee43c27ab3344d6aa82fa609"),
-            Utils.decodeCompactBits(0x1b06f8f0), true);
+        assertThrows("AuxPow is not a generate", org.bitcoinj.core.VerificationException.class, () -> {
+            auxpow.checkProofOfWork(Sha256Hash.wrap("0c836b86991631d34a8a68054e2f62db919b39d1ee43c27ab3344d6aa82fa609"),
+                    Utils.decodeCompactBits(0x1b06f8f0), true);
+        });
     }
 
     /**
@@ -116,16 +114,17 @@ public void shouldRejectNonGenerateAuxPoW() throws Exception {
     @Test
     public void shouldRejectOwnChainID() throws Exception {
         byte[] payload = Util.getBytes(getClass().getResourceAsStream("dogecoin_block371337.bin"));
-        AltcoinSerializer serializer = (AltcoinSerializer)params.getDefaultSerializer();
-        final AltcoinBlock block = (AltcoinBlock)serializer.makeBlock(payload);
+        AltcoinSerializer serializer = (AltcoinSerializer) params.getDefaultSerializer();
+        final AltcoinBlock block = (AltcoinBlock) serializer.makeBlock(payload);
         assertEquals(98, block.getChainID());
         final AuxPoW auxpow = block.getAuxPoW();
         assertNotNull(auxpow);
-        auxpow.setParentBlockHeader((AltcoinBlock)block.cloneAsHeader());
-        expectedEx.expect(org.bitcoinj.core.VerificationException.class);
-        expectedEx.expectMessage("Aux POW parent has our chain ID");
-        auxpow.checkProofOfWork(Sha256Hash.wrap("0c836b86991631d34a8a68054e2f62db919b39d1ee43c27ab3344d6aa82fa609"),
-            Utils.decodeCompactBits(0x1b06f8f0), true);
+        auxpow.setParentBlockHeader((AltcoinBlock) block.cloneAsHeader());
+        assertThrows("Aux POW parent has our chain ID",
+                org.bitcoinj.core.VerificationException.class, () -> {
+                    auxpow.checkProofOfWork(Sha256Hash.wrap("0c836b86991631d34a8a68054e2f62db919b39d1ee43c27ab3344d6aa82fa609"),
+                            Utils.decodeCompactBits(0x1b06f8f0), true);
+                });
     }
 
     /**
@@ -134,12 +133,12 @@ public void shouldRejectOwnChainID() throws Exception {
     @Test
     public void shouldRejectVeryLongMerkleBranch() throws Exception {
         final byte[] auxpowAsBytes = getBytes(getClass().getResourceAsStream("auxpow_header.bin"));
-        final AuxPoW auxpow = new AuxPoW(params, auxpowAsBytes, (ChildMessage) null, params.getDefaultSerializer());
+        final AuxPoW auxpow = new AuxPoW(params, auxpowAsBytes, null, params.getDefaultSerializer());
         auxpow.getChainMerkleBranch().setHashes(Arrays.asList(new Sha256Hash[32]));
-        expectedEx.expect(org.bitcoinj.core.VerificationException.class);
-        expectedEx.expectMessage("Aux POW chain merkle branch too long");
-        auxpow.checkProofOfWork(Sha256Hash.wrap("0c836b86991631d34a8a68054e2f62db919b39d1ee43c27ab3344d6aa82fa609"),
-            Utils.decodeCompactBits(0x1b06f8f0), true);
+        assertThrows("Aux POW chain merkle branch too long", org.bitcoinj.core.VerificationException.class, () -> {
+            auxpow.checkProofOfWork(Sha256Hash.wrap("0c836b86991631d34a8a68054e2f62db919b39d1ee43c27ab3344d6aa82fa609"),
+                    Utils.decodeCompactBits(0x1b06f8f0), true);
+        });
     }
 
     /**
@@ -152,12 +151,12 @@ public void shouldRejectVeryLongMerkleBranch() throws Exception {
     @Test
     public void shouldRejectIfCoinbaseTransactionNotInMerkleBranch() throws Exception {
         final byte[] auxpowAsBytes = getBytes(getClass().getResourceAsStream("auxpow_header.bin"));
-        final AuxPoW auxpow = new AuxPoW(params, auxpowAsBytes, (ChildMessage) null, params.getDefaultSerializer());
+        final AuxPoW auxpow = new AuxPoW(params, auxpowAsBytes, null, params.getDefaultSerializer());
         auxpow.getCoinbase().clearOutputs();
-        expectedEx.expect(org.bitcoinj.core.VerificationException.class);
-        expectedEx.expectMessage("Aux POW merkle root incorrect");
-        auxpow.checkProofOfWork(Sha256Hash.wrap("0c836b86991631d34a8a68054e2f62db919b39d1ee43c27ab3344d6aa82fa609"),
-            Utils.decodeCompactBits(0x1b06f8f0), true);
+        assertThrows("Aux POW merkle root incorrect", org.bitcoinj.core.VerificationException.class, () -> {
+            auxpow.checkProofOfWork(Sha256Hash.wrap("0c836b86991631d34a8a68054e2f62db919b39d1ee43c27ab3344d6aa82fa609"),
+                    Utils.decodeCompactBits(0x1b06f8f0), true);
+        });
     }
 
     /**
@@ -167,17 +166,18 @@ public void shouldRejectIfCoinbaseTransactionNotInMerkleBranch() throws Exceptio
     @Test
     public void shouldRejectIfCoinbaseTransactionHasNoInputs() throws Exception {
         final byte[] auxpowAsBytes = getBytes(getClass().getResourceAsStream("auxpow_header.bin"));
-        final AuxPoW auxpow = new AuxPoW(params, auxpowAsBytes, (ChildMessage) null, params.getDefaultSerializer());
+        final AuxPoW auxpow = new AuxPoW(params, auxpowAsBytes, null, params.getDefaultSerializer());
 
         // This will also break the difficulty check, but as that doesn't occur
         // until the end, we can get away with it.
         auxpow.getCoinbase().clearInputs();
         updateMerkleRootToMatchCoinbase(auxpow);
 
-        expectedEx.expect(org.bitcoinj.core.VerificationException.class);
-        expectedEx.expectMessage("Coinbase transaction has no inputs");
-        auxpow.checkProofOfWork(Sha256Hash.wrap("0c836b86991631d34a8a68054e2f62db919b39d1ee43c27ab3344d6aa82fa609"),
-            Utils.decodeCompactBits(0x1b06f8f0), true);
+        assertThrows("Coinbase transaction has no inputs",
+                org.bitcoinj.core.VerificationException.class, () -> {
+            auxpow.checkProofOfWork(Sha256Hash.wrap("0c836b86991631d34a8a68054e2f62db919b39d1ee43c27ab3344d6aa82fa609"),
+                    Utils.decodeCompactBits(0x1b06f8f0), true);
+        });
     }
 
     /**
@@ -188,7 +188,7 @@ public void shouldRejectIfCoinbaseTransactionHasNoInputs() throws Exception {
     @Test
     public void shouldRejectIfMergedMineHeaderMissing() throws Exception {
         final byte[] auxpowAsBytes = getBytes(getClass().getResourceAsStream("auxpow_header.bin"));
-        final AuxPoW auxpow = new AuxPoW(params, auxpowAsBytes, (ChildMessage) null, params.getDefaultSerializer());
+        final AuxPoW auxpow = new AuxPoW(params, auxpowAsBytes, null, params.getDefaultSerializer());
 
         // This will also break the difficulty check, but as that doesn't occur
         // until the end, we can get away with it.
@@ -199,20 +199,21 @@ public void shouldRejectIfMergedMineHeaderMissing() throws Exception {
         in.setScriptBytes(paddedScriptBytes);
         updateMerkleRootToMatchCoinbase(auxpow);
 
-        expectedEx.expect(org.bitcoinj.core.VerificationException.class);
-        expectedEx.expectMessage("Aux POW chain merkle root must start in the first 20 bytes of the parent coinbase");
-        auxpow.checkProofOfWork(Sha256Hash.wrap("0c836b86991631d34a8a68054e2f62db919b39d1ee43c27ab3344d6aa82fa609"),
-            Utils.decodeCompactBits(0x1b06f8f0), true);
+        assertThrows("Aux POW chain merkle root must start in the first 20 bytes of the parent coinbase",
+                org.bitcoinj.core.VerificationException.class, () -> {
+            auxpow.checkProofOfWork(Sha256Hash.wrap("0c836b86991631d34a8a68054e2f62db919b39d1ee43c27ab3344d6aa82fa609"),
+                    Utils.decodeCompactBits(0x1b06f8f0), true);
+        });
     }
 
     /**
-     * Catch the case that more than one merged mine header is present in the 
+     * Catch the case that more than one merged mine header is present in the
      * coinbase transaction (this is considered an attempt to confuse the parser).
      */
     @Test
     public void shouldRejectIfMergedMineHeaderDuplicated() throws Exception {
         final byte[] auxpowAsBytes = getBytes(getClass().getResourceAsStream("auxpow_header.bin"));
-        final AuxPoW auxpow = new AuxPoW(params, auxpowAsBytes, (ChildMessage) null, params.getDefaultSerializer());
+        final AuxPoW auxpow = new AuxPoW(params, auxpowAsBytes, null, params.getDefaultSerializer());
 
         // This will also break the difficulty check, but as that doesn't occur
         // until the end, we can get away with it.
@@ -224,12 +225,14 @@ public void shouldRejectIfMergedMineHeaderDuplicated() throws Exception {
         in.setScriptBytes(newBytes);
         updateMerkleRootToMatchCoinbase(auxpow);
 
-        expectedEx.expect(org.bitcoinj.core.VerificationException.class);
-        expectedEx.expectMessage("Multiple merged mining headers in coinbase");
-        auxpow.checkProofOfWork(Sha256Hash.wrap("0c836b86991631d34a8a68054e2f62db919b39d1ee43c27ab3344d6aa82fa609"),
-            Utils.decodeCompactBits(0x1b06f8f0), true);
+        assertThrows("Multiple merged mining headers in coinbase",
+                org.bitcoinj.core.VerificationException.class, () -> {
+            auxpow.checkProofOfWork(Sha256Hash.wrap("0c836b86991631d34a8a68054e2f62db919b39d1ee43c27ab3344d6aa82fa609"),
+                    Utils.decodeCompactBits(0x1b06f8f0), true);
+        });
     }
 
+
     /**
      * Catch the case that the chain merkle branch is missing from the coinbase
      * transaction. The chain merkle branch is used to prove that the block was
@@ -239,7 +242,7 @@ public void shouldRejectIfMergedMineHeaderDuplicated() throws Exception {
     @Test
     public void shouldRejectIfCoinbaseMissingChainMerkleRoot() throws Exception {
         final byte[] auxpowAsBytes = getBytes(getClass().getResourceAsStream("auxpow_header.bin"));
-        final AuxPoW auxpow = new AuxPoW(params, auxpowAsBytes, (ChildMessage) null, params.getDefaultSerializer());
+        final AuxPoW auxpow = new AuxPoW(params, auxpowAsBytes, null, params.getDefaultSerializer());
 
         // This will also break the difficulty check, but as that doesn't occur
         // until the end, we can get away with it.
@@ -247,10 +250,11 @@ public void shouldRejectIfCoinbaseMissingChainMerkleRoot() throws Exception {
         in.getScriptBytes()[8] = 0; // Break the first byte of the chain merkle root
         updateMerkleRootToMatchCoinbase(auxpow);
 
-        expectedEx.expect(org.bitcoinj.core.VerificationException.class);
-        expectedEx.expectMessage("Aux POW missing chain merkle root in parent coinbase");
-        auxpow.checkProofOfWork(Sha256Hash.wrap("0c836b86991631d34a8a68054e2f62db919b39d1ee43c27ab3344d6aa82fa609"),
-            Utils.decodeCompactBits(0x1b06f8f0), true);
+        assertThrows("Aux POW missing chain merkle root in parent coinbase",
+                org.bitcoinj.core.VerificationException.class, () -> {
+            auxpow.checkProofOfWork(Sha256Hash.wrap("0c836b86991631d34a8a68054e2f62db919b39d1ee43c27ab3344d6aa82fa609"),
+                    Utils.decodeCompactBits(0x1b06f8f0), true);
+        });
     }
 
     /**
@@ -261,7 +265,7 @@ public void shouldRejectIfCoinbaseMissingChainMerkleRoot() throws Exception {
     @Test
     public void shouldRejectIfChainMerkleRootNotAfterHeader() throws Exception {
         final byte[] auxpowAsBytes = getBytes(getClass().getResourceAsStream("auxpow_header.bin"));
-        final AuxPoW auxpow = new AuxPoW(params, auxpowAsBytes, (ChildMessage) null, params.getDefaultSerializer());
+        final AuxPoW auxpow = new AuxPoW(params, auxpowAsBytes, null, params.getDefaultSerializer());
 
         // This will also break the difficulty check, but as that doesn't occur
         // until the end, we can get away with it.
@@ -277,10 +281,11 @@ public void shouldRejectIfChainMerkleRootNotAfterHeader() throws Exception {
         in.setScriptBytes(newBytes);
         updateMerkleRootToMatchCoinbase(auxpow);
 
-        expectedEx.expect(org.bitcoinj.core.VerificationException.class);
-        expectedEx.expectMessage("Merged mining header is not just before chain merkle root");
-        auxpow.checkProofOfWork(Sha256Hash.wrap("0c836b86991631d34a8a68054e2f62db919b39d1ee43c27ab3344d6aa82fa609"),
-            Utils.decodeCompactBits(0x1b06f8f0), true);
+        assertThrows("Merged mining header is not just before chain merkle root",
+                org.bitcoinj.core.VerificationException.class, () -> {
+            auxpow.checkProofOfWork(Sha256Hash.wrap("0c836b86991631d34a8a68054e2f62db919b39d1ee43c27ab3344d6aa82fa609"),
+                    Utils.decodeCompactBits(0x1b06f8f0), true);
+        });
     }
 
     /**
@@ -291,7 +296,7 @@ public void shouldRejectIfChainMerkleRootNotAfterHeader() throws Exception {
     @Test
     public void shouldRejectIfScriptBytesTooShort() throws Exception {
         final byte[] auxpowAsBytes = getBytes(getClass().getResourceAsStream("auxpow_header.bin"));
-        final AuxPoW auxpow = new AuxPoW(params, auxpowAsBytes, (ChildMessage) null, params.getDefaultSerializer());
+        final AuxPoW auxpow = new AuxPoW(params, auxpowAsBytes, null, params.getDefaultSerializer());
 
         // This will also break the difficulty check, but as that doesn't occur
         // until the end, we can get away with it.
@@ -300,10 +305,11 @@ public void shouldRejectIfScriptBytesTooShort() throws Exception {
         in.setScriptBytes(newBytes);
         updateMerkleRootToMatchCoinbase(auxpow);
 
-        expectedEx.expect(org.bitcoinj.core.VerificationException.class);
-        expectedEx.expectMessage("Aux POW missing chain merkle tree size and nonce in parent coinbase");
-        auxpow.checkProofOfWork(Sha256Hash.wrap("0c836b86991631d34a8a68054e2f62db919b39d1ee43c27ab3344d6aa82fa609"),
-            Utils.decodeCompactBits(0x1b06f8f0), true);
+        assertThrows("Aux POW missing chain merkle tree size and nonce in parent coinbase",
+                org.bitcoinj.core.VerificationException.class, () -> {
+            auxpow.checkProofOfWork(Sha256Hash.wrap("0c836b86991631d34a8a68054e2f62db919b39d1ee43c27ab3344d6aa82fa609"),
+                    Utils.decodeCompactBits(0x1b06f8f0), true);
+        });
     }
 
     /**
@@ -313,7 +319,7 @@ public void shouldRejectIfScriptBytesTooShort() throws Exception {
     @Test
     public void shouldRejectIfCoinbaseMerkleBranchSizeMismatch() throws Exception {
         final byte[] auxpowAsBytes = getBytes(getClass().getResourceAsStream("auxpow_header.bin"));
-        final AuxPoW auxpow = new AuxPoW(params, auxpowAsBytes, (ChildMessage) null, params.getDefaultSerializer());
+        final AuxPoW auxpow = new AuxPoW(params, auxpowAsBytes, null, params.getDefaultSerializer());
 
         // This will also break the difficulty check, but as that doesn't occur
         // until the end, we can get away with it.
@@ -321,10 +327,11 @@ public void shouldRejectIfCoinbaseMerkleBranchSizeMismatch() throws Exception {
         in.getScriptBytes()[40] = 3; // Break the merkle branch length
         updateMerkleRootToMatchCoinbase(auxpow);
 
-        expectedEx.expect(org.bitcoinj.core.VerificationException.class);
-        expectedEx.expectMessage("Aux POW merkle branch size does not match parent coinbase");
-        auxpow.checkProofOfWork(Sha256Hash.wrap("0c836b86991631d34a8a68054e2f62db919b39d1ee43c27ab3344d6aa82fa609"),
-            Utils.decodeCompactBits(0x1b06f8f0), true);
+        assertThrows("Aux POW merkle branch size does not match parent coinbase",
+                org.bitcoinj.core.VerificationException.class, () -> {
+            auxpow.checkProofOfWork(Sha256Hash.wrap("0c836b86991631d34a8a68054e2f62db919b39d1ee43c27ab3344d6aa82fa609"),
+                    Utils.decodeCompactBits(0x1b06f8f0), true);
+        });
     }
 
     /**
@@ -334,7 +341,7 @@ public void shouldRejectIfCoinbaseMerkleBranchSizeMismatch() throws Exception {
     @Test
     public void shouldRejectIfNonceIncorrect() throws Exception {
         final byte[] auxpowAsBytes = getBytes(getClass().getResourceAsStream("auxpow_header.bin"));
-        final AuxPoW auxpow = new AuxPoW(params, auxpowAsBytes, (ChildMessage) null, params.getDefaultSerializer());
+        final AuxPoW auxpow = new AuxPoW(params, auxpowAsBytes, null, params.getDefaultSerializer());
 
         // This will also break the difficulty check, but as that doesn't occur
         // until the end, we can get away with it.
@@ -342,10 +349,11 @@ public void shouldRejectIfNonceIncorrect() throws Exception {
         in.getScriptBytes()[44] = (byte) 0xff; // Break the nonce value
         updateMerkleRootToMatchCoinbase(auxpow);
 
-        expectedEx.expect(org.bitcoinj.core.VerificationException.class);
-        expectedEx.expectMessage("Aux POW wrong index");
-        auxpow.checkProofOfWork(Sha256Hash.wrap("0c836b86991631d34a8a68054e2f62db919b39d1ee43c27ab3344d6aa82fa609"),
-            Utils.decodeCompactBits(0x1b06f8f0), true);
+        assertThrows("Aux POW wrong index",
+                org.bitcoinj.core.VerificationException.class, () -> {
+            auxpow.checkProofOfWork(Sha256Hash.wrap("0c836b86991631d34a8a68054e2f62db919b39d1ee43c27ab3344d6aa82fa609"),
+                    Utils.decodeCompactBits(0x1b06f8f0), true);
+        });
     }
 
     /**
@@ -355,13 +363,13 @@ public void shouldRejectIfNonceIncorrect() throws Exception {
     @Test
     public void shouldRejectHashAboveTarget() throws Exception {
         final byte[] auxpowAsBytes = getBytes(getClass().getResourceAsStream("auxpow_header.bin"));
-        final AuxPoW auxpow = new AuxPoW(params, auxpowAsBytes, (ChildMessage) null, params.getDefaultSerializer());
+        final AuxPoW auxpow = new AuxPoW(params, auxpowAsBytes, null, params.getDefaultSerializer());
 
-        expectedEx.expect(org.bitcoinj.core.VerificationException.class);
-        expectedEx.expectMessage("Hash is higher than target: 000000000003178bb23160cdbc81af53f47cae9f479acf1e69849da42fd5bfca vs 0");
-        
-        auxpow.checkProofOfWork(Sha256Hash.wrap("0c836b86991631d34a8a68054e2f62db919b39d1ee43c27ab3344d6aa82fa609"),
-            Utils.decodeCompactBits(0x00), true);
+        assertThrows("Hash is higher than target: 000000000003178bb23160cdbc81af53f47cae9f479acf1e69849da42fd5bfca vs 0",
+                org.bitcoinj.core.VerificationException.class, () -> {
+            auxpow.checkProofOfWork(Sha256Hash.wrap("0c836b86991631d34a8a68054e2f62db919b39d1ee43c27ab3344d6aa82fa609"),
+                    Utils.decodeCompactBits(0x00), true);
+        });
     }
 
     /**
@@ -371,12 +379,12 @@ public void shouldRejectHashAboveTarget() throws Exception {
     private void updateMerkleRootToMatchCoinbase(final AuxPoW auxpow) {
         final Transaction coinbase = auxpow.getCoinbase();
 
-        final Sha256Hash revisedCoinbaseHash = coinbase.getHash();
+        final Sha256Hash revisedCoinbaseHash = coinbase.getTxId();
         // The coinbase hash is the single leaf node in the merkle tree,
         // so to get the root we need to hash it with itself.
         // Note that bytes are reversed for hashing
         final Sha256Hash revisedMerkleRoot = Sha256Hash.wrapReversed(
-            Sha256Hash.hashTwice(revisedCoinbaseHash.getReversedBytes(), 0, 32, revisedCoinbaseHash.getReversedBytes(), 0, 32)
+                Sha256Hash.hashTwice(revisedCoinbaseHash.getReversedBytes(), 0, 32, revisedCoinbaseHash.getReversedBytes(), 0, 32)
         );
         auxpow.getParentBlockHeader().setMerkleRoot(revisedMerkleRoot);
         auxpow.setCoinbaseBranch(new MerkleBranch(params, auxpow,
diff --git a/core/src/test/java/org/bitcoinj/core/DogecoinBlockTest.java b/core/src/test/java/org/bitcoinj/core/DogecoinBlockTest.java
index 156476861..d967c3fd7 100644
--- a/core/src/test/java/org/bitcoinj/core/DogecoinBlockTest.java
+++ b/core/src/test/java/org/bitcoinj/core/DogecoinBlockTest.java
@@ -1,28 +1,20 @@
-/*
- * To change this license header, choose License Headers in Project Properties.
- * To change this template file, choose Tools | Templates
- * and open the template in the editor.
- */
 package org.bitcoinj.core;
 
+import org.junit.Before;
+import org.junit.Test;
 import org.libdohj.core.AltcoinSerializer;
-import java.io.IOException;
-import java.math.BigInteger;
 import org.libdohj.params.DogecoinMainNetParams;
+
+import java.io.IOException;
+
 import static org.junit.Assert.assertArrayEquals;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
-import org.junit.Before;
-import org.junit.Test;
 
-/**
- *
- * @author jrn
- */
 public class DogecoinBlockTest {
-    private final NetworkParameters params = DogecoinMainNetParams.get();
+    private static final NetworkParameters params = DogecoinMainNetParams.get();
 
     @Before
     public void setUp() throws Exception {
@@ -59,7 +51,6 @@ public void shouldParseBlock1() throws IOException {
 
     /**
      * Test the first hardfork block.
-     * @throws IOException 
      */
     @Test
     public void shouldParseBlock250000() throws IOException {
@@ -76,8 +67,6 @@ public void shouldParseBlock250000() throws IOException {
 
     /**
      * Confirm parsing of the first merged-mine block.
-     * 
-     * @throws IOException 
      */
     @Test
     public void shouldParseBlock371337() throws IOException {
@@ -125,8 +114,6 @@ public void shouldParseBlock371337() throws IOException {
     /**
      * Confirm parsing of block with a nonce value above Integer.MAX_VALUE.
      * See https://github.com/rnicoll/libdohj/pull/7
-     * 
-     * @throws IOException 
      */
     @Test
     public void shouldParseBlock748634() throws IOException {
@@ -150,8 +137,6 @@ public void shouldParseBlock748634() throws IOException {
     /**
      * Confirm parsing of block with a nonce value above Integer.MAX_VALUE.
      * See https://github.com/rnicoll/libdohj/issues/5
-     * 
-     * @throws IOException 
      */
     @Test
     public void shouldParseBlock894863() throws IOException {
diff --git a/core/src/test/java/org/bitcoinj/core/LitecoinBlockTest.java b/core/src/test/java/org/bitcoinj/core/LitecoinBlockTest.java
index 0459c425f..145ff8820 100644
--- a/core/src/test/java/org/bitcoinj/core/LitecoinBlockTest.java
+++ b/core/src/test/java/org/bitcoinj/core/LitecoinBlockTest.java
@@ -1,26 +1,17 @@
-/*
- * To change this license header, choose License Headers in Project Properties.
- * To change this template file, choose Tools | Templates
- * and open the template in the editor.
- */
 package org.bitcoinj.core;
 
-import java.io.IOException;
-
+import org.junit.Before;
+import org.junit.Test;
 import org.libdohj.core.AltcoinSerializer;
 import org.libdohj.params.LitecoinMainNetParams;
 
+import java.io.IOException;
+
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertTrue;
-import org.junit.Before;
-import org.junit.Test;
 
-/**
- *
- * @author jrn
- */
 public class LitecoinBlockTest {
-    private NetworkParameters params = LitecoinMainNetParams.get();
+    private static final NetworkParameters params = LitecoinMainNetParams.get();
 
     @Before
     public void setUp() throws Exception {
diff --git a/core/src/test/java/org/bitcoinj/core/MerkleBranchTest.java b/core/src/test/java/org/bitcoinj/core/MerkleBranchTest.java
index 49b16d75e..206198a59 100644
--- a/core/src/test/java/org/bitcoinj/core/MerkleBranchTest.java
+++ b/core/src/test/java/org/bitcoinj/core/MerkleBranchTest.java
@@ -1,12 +1,10 @@
 package org.bitcoinj.core;
 
 
-import static org.bitcoinj.core.AuxPoWTest.params;
 import org.bitcoinj.params.TestNet3Params;
 import org.junit.Test;
 
 import static org.bitcoinj.core.Util.getBytes;
-
 import static org.junit.Assert.assertArrayEquals;
 import static org.junit.Assert.assertEquals;
 
diff --git a/core/src/test/java/org/bitcoinj/core/Util.java b/core/src/test/java/org/bitcoinj/core/Util.java
index 62907d52c..1003ddefd 100644
--- a/core/src/test/java/org/bitcoinj/core/Util.java
+++ b/core/src/test/java/org/bitcoinj/core/Util.java
@@ -1,18 +1,9 @@
-/*
- * To change this license header, choose License Headers in Project Properties.
- * To change this template file, choose Tools | Templates
- * and open the template in the editor.
- */
 package org.bitcoinj.core;
 
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 
-/**
- *
- * @author jrn
- */
 public class Util {
 
     public static byte[] getBytes(InputStream inputStream) throws IOException {
diff --git a/core/src/test/java/org/libdohj/names/NameTransactionUtilsTest.java b/core/src/test/java/org/libdohj/names/NameTransactionUtilsTest.java
index f9d22d2ac..064862908 100644
--- a/core/src/test/java/org/libdohj/names/NameTransactionUtilsTest.java
+++ b/core/src/test/java/org/libdohj/names/NameTransactionUtilsTest.java
@@ -15,6 +15,8 @@
  */
 package org.libdohj.names;
 
+import org.junit.Before;
+import org.junit.Test;
 import org.libdohj.params.AbstractNamecoinParams;
 import org.libdohj.params.NamecoinMainNetParams;
 
@@ -24,8 +26,6 @@
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNull;
-import org.junit.Before;
-import org.junit.Test;
 
 import java.io.IOException;
 
diff --git a/core/src/test/java/org/libdohj/params/AbstractDogecoinParamsTest.java b/core/src/test/java/org/libdohj/params/AbstractDogecoinParamsTest.java
index 444e259c8..9b570eaee 100644
--- a/core/src/test/java/org/libdohj/params/AbstractDogecoinParamsTest.java
+++ b/core/src/test/java/org/libdohj/params/AbstractDogecoinParamsTest.java
@@ -15,17 +15,16 @@
  */
 package org.libdohj.params;
 
-import java.io.IOException;
-import org.bitcoinj.core.AltcoinBlock;
-import org.bitcoinj.core.Coin;
-import org.bitcoinj.core.Context;
-import org.bitcoinj.core.Sha256Hash;
-import org.bitcoinj.core.Util;
-import static org.junit.Assert.assertEquals;
+import org.bitcoinj.core.*;
 import org.junit.Before;
 import org.junit.Test;
 import org.libdohj.core.AltcoinSerializer;
 
+import java.io.IOException;
+
+
+import static org.junit.Assert.assertEquals;
+
 /**
  *
  * @author Ross Nicoll
diff --git a/core/src/test/java/org/libdohj/params/AbstractLitecoinParamsTest.java b/core/src/test/java/org/libdohj/params/AbstractLitecoinParamsTest.java
index 3f71928b0..e34b1cee4 100644
--- a/core/src/test/java/org/libdohj/params/AbstractLitecoinParamsTest.java
+++ b/core/src/test/java/org/libdohj/params/AbstractLitecoinParamsTest.java
@@ -17,10 +17,11 @@
 
 import org.bitcoinj.core.Coin;
 import org.bitcoinj.core.Context;
-import static org.junit.Assert.assertEquals;
 import org.junit.Before;
 import org.junit.Test;
 
+import static org.junit.Assert.assertEquals;
+
 /**
  *
  * @author Ross Nicoll
diff --git a/core/src/test/java/org/libdohj/params/LitecoinTestNet3ParamsTest.java b/core/src/test/java/org/libdohj/params/LitecoinTestNet3ParamsTest.java
index fefc877f1..d2c023f54 100644
--- a/core/src/test/java/org/libdohj/params/LitecoinTestNet3ParamsTest.java
+++ b/core/src/test/java/org/libdohj/params/LitecoinTestNet3ParamsTest.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2015 J. Ross Nicoll
+ * Copyright 2015, 2021 J. Ross Nicoll
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,10 +16,11 @@
 package org.libdohj.params;
 
 import org.bitcoinj.core.Context;
-import static org.junit.Assert.assertEquals;
 import org.junit.Before;
 import org.junit.Test;
 
+import static org.junit.Assert.assertEquals;
+
 /**
  *
  * @author Ross Nicoll
diff --git a/core/src/test/java/org/libdohj/script/NameScriptTest.java b/core/src/test/java/org/libdohj/script/NameScriptTest.java
index f936bbb72..c14bf1583 100644
--- a/core/src/test/java/org/libdohj/script/NameScriptTest.java
+++ b/core/src/test/java/org/libdohj/script/NameScriptTest.java
@@ -25,17 +25,16 @@
 import org.bitcoinj.script.Script;
 
 import org.junit.Before;
-import org.junit.Rule;
 import org.junit.Test;
+
+import java.io.IOException;
+
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertThrows;
 import static org.junit.Assert.assertTrue;
-import org.junit.rules.ExpectedException;
-
-import java.io.IOException;
 
 /**
- *
  * @author Jeremy Rand
  */
 public class NameScriptTest {
@@ -46,310 +45,302 @@ public void setUp() throws Exception {
         Context context = new Context(params);
     }
 
-    @Rule
-    public ExpectedException expectedEx = ExpectedException.none();
-    
     @Test
     public void nameNewIsNameOp() throws IOException {
         final NameScript ns = getNameNewNameScript();
-        
+
         assertTrue(ns.isNameOp());
     }
-    
+
     @Test
     public void nameNewGetAddress() throws IOException {
         final NameScript ns = getNameNewNameScript();
-        
+
         assertEquals("MyVbKbD4MYNUMEpdNAm3Jd3nbr5t8djALC", ns.getAddress().getToAddress(params).toString());
     }
-    
+
     // TODO: getNameOp when it's implemented
-    
+
     @Test
     public void nameNewIsAnyUpdate() throws IOException {
         final NameScript ns = getNameNewNameScript();
-        
+
         assertFalse(ns.isAnyUpdate());
     }
-    
+
     @Test
     public void nameNewGetOpName() throws IOException {
         final NameScript ns = getNameNewNameScript();
-        
-        expectedEx.expect(org.bitcoinj.script.ScriptException.class);
-        expectedEx.expectMessage("Not an AnyUpdate op");
-        ns.getOpName();
+
+        assertThrows("Not an AnyUpdate op",
+                org.bitcoinj.script.ScriptException.class, () -> ns.getOpName());
     }
-        
+
     @Test
     public void nameNewGetOpValue() throws IOException {
         final NameScript ns = getNameNewNameScript();
-        
-        expectedEx.expect(org.bitcoinj.script.ScriptException.class);
-        expectedEx.expectMessage("Not an AnyUpdate op");
-        ns.getOpValue();
-        
+
+        assertThrows("Not an AnyUpdate op",
+                org.bitcoinj.script.ScriptException.class, () -> ns.getOpValue());
+
     }
-    
+
     // TODO: getOpRand, getOpHash, isNameScript when they're implemented
-    
+
     @Test
     public void nameFirstUpdateIsNameOp() throws IOException {
         final NameScript ns = getNameFirstUpdateNameScript();
-        
+
         assertTrue(ns.isNameOp());
     }
-    
+
     @Test
     public void nameFirstUpdateGetAddress() throws IOException {
         final NameScript ns = getNameFirstUpdateNameScript();
-        
+
         assertEquals("NGcTVLgw6cgdavaE7C9QvWaY7gKiWbLrjP", ns.getAddress().getToAddress(params).toString());
     }
-    
+
     // TODO: getNameOp when it's implemented
-    
+
     @Test
     public void nameFirstUpdateIsAnyUpdate() throws IOException {
         final NameScript ns = getNameFirstUpdateNameScript();
-        
+
         assertTrue(ns.isAnyUpdate());
     }
-    
+
     @Test
     public void nameFirstUpdateGetOpName() throws IOException {
         final NameScript ns = getNameFirstUpdateNameScript();
-        
+
         assertEquals("d/bitcoin", new String(ns.getOpName().data, "ISO-8859-1"));
     }
-        
+
     @Test
     public void nameFirstUpdateGetOpValue() throws IOException {
         final NameScript ns = getNameFirstUpdateNameScript();
-        
+
         assertEquals("webpagedeveloper.me/namecoin", new String(ns.getOpValue().data, "ISO-8859-1"));
     }
-    
+
     // TODO: getOpRand, getOpHash, isNameScript when they're implemented
-    
+
     @Test
     public void nameUpdateIsNameOp() throws IOException {
         final NameScript ns = getNameUpdateNameScript();
-        
+
         assertTrue(ns.isNameOp());
     }
-    
+
     @Test
     public void nameUpdateGetAddress() throws IOException {
         final NameScript ns = getNameUpdateNameScript();
-        
+
         assertEquals("N9dLs1zHRfZr5cJNjSrvhWrrUcmNSthdmz", ns.getAddress().getToAddress(params).toString());
     }
-    
+
     // TODO: getNameOp when it's implemented
-    
+
     @Test
     public void nameUpdateIsAnyUpdate() throws IOException {
         final NameScript ns = getNameUpdateNameScript();
-        
+
         assertTrue(ns.isAnyUpdate());
     }
-    
+
     @Test
     public void nameUpdateGetOpName() throws IOException {
         final NameScript ns = getNameUpdateNameScript();
-        
+
         assertEquals("d/bitcoin", new String(ns.getOpName().data, "ISO-8859-1"));
     }
-        
+
     @Test
     public void nameUpdateGetOpValue() throws IOException {
         final NameScript ns = getNameUpdateNameScript();
-        
+
         assertEquals("{\"info\":{\"registrar\":\"http://register.dot-bit.org\"},\"email\": \"register@dot-bit.org\",\"ns\":[\"ns0.web-sweet-web.net\",\"ns1.web-sweet-web.net\"],\"map\":{\"\":{\"ns\":[\"ns0.web-sweet-web.net\",\"ns1.web-sweet-web.net\"]}}}", new String(ns.getOpValue().data, "ISO-8859-1"));
     }
-    
+
     // TODO: getOpRand, getOpHash, isNameScript when they're implemented
-    
+
     @Test
     public void currencyIsNameOp() throws IOException {
         final NameScript ns = getCurrencyNameScript();
-        
+
         assertFalse(ns.isNameOp());
     }
-    
+
     @Test
     public void currencyGetAddress() throws IOException {
         final NameScript ns = getCurrencyNameScript();
-        
+
         assertEquals("NCMmrGC7uaJ3uv8feLgBTtwGLQSWfmxMCk", ns.getAddress().getToAddress(params).toString());
     }
-    
+
     // TODO: getNameOp when it's implemented
-    
+
     @Test
     public void currencyIsAnyUpdate() throws IOException {
         final NameScript ns = getCurrencyNameScript();
-        
-        expectedEx.expect(org.bitcoinj.script.ScriptException.class);
-        expectedEx.expectMessage("Not a name op");
-        ns.isAnyUpdate();
+
+        assertThrows("Not a name op",
+                org.bitcoinj.script.ScriptException.class, () -> ns.isAnyUpdate());
     }
-    
+
     @Test
     public void currencyGetOpName() throws IOException {
         final NameScript ns = getCurrencyNameScript();
-        
-        expectedEx.expect(org.bitcoinj.script.ScriptException.class);
-        expectedEx.expectMessage("Not an AnyUpdate op");
-        ns.getOpName();
+
+        assertThrows("Not an AnyUpdate op",
+                org.bitcoinj.script.ScriptException.class, () -> ns.getOpName());
     }
-        
+
     @Test
     public void currencyGetOpValue() throws IOException {
         final NameScript ns = getCurrencyNameScript();
-        
-        expectedEx.expect(org.bitcoinj.script.ScriptException.class);
-        expectedEx.expectMessage("Not an AnyUpdate op");
-        ns.getOpValue();
+
+        assertThrows("Not an AnyUpdate op",
+                org.bitcoinj.script.ScriptException.class, () -> ns.getOpValue());
     }
-    
+
     // TODO: getOpRand, getOpHash, isNameScript when they're implemented
-    
+
     @Test
     public void returnIsNameOp() throws IOException {
         final NameScript ns = getReturnNameScript();
-        
+
         assertFalse(ns.isNameOp());
     }
-    
+
     @Test
     public void returnGetAddress() throws IOException {
         final NameScript ns = getReturnNameScript();
-        
-        expectedEx.expect(org.bitcoinj.script.ScriptException.class);
-        expectedEx.expectMessage("Cannot cast this script to an address");
-        ns.getAddress().getToAddress(params).toString();
+
+        assertThrows("Cannot cast this script to an address",
+                org.bitcoinj.script.ScriptException.class,
+                () -> ns.getAddress().getToAddress(params).toString());
     }
-    
+
     // TODO: getNameOp when it's implemented
-    
+
     @Test
     public void returnIsAnyUpdate() throws IOException {
         final NameScript ns = getReturnNameScript();
-        
-        expectedEx.expect(org.bitcoinj.script.ScriptException.class);
-        expectedEx.expectMessage("Not a name op");
-        ns.isAnyUpdate();
+
+        assertThrows("Not a name op",
+                org.bitcoinj.script.ScriptException.class,
+                () -> ns.isAnyUpdate());
     }
-    
+
     @Test
     public void returnGetOpName() throws IOException {
         final NameScript ns = getReturnNameScript();
-        
-        expectedEx.expect(org.bitcoinj.script.ScriptException.class);
-        expectedEx.expectMessage("Not an AnyUpdate op");
-        ns.getOpName();
+
+        assertThrows("Not an AnyUpdate op",
+                org.bitcoinj.script.ScriptException.class,
+                () -> ns.getOpName());
     }
-        
+
     @Test
     public void returnGetOpValue() throws IOException {
         final NameScript ns = getReturnNameScript();
-        
-        expectedEx.expect(org.bitcoinj.script.ScriptException.class);
-        expectedEx.expectMessage("Not an AnyUpdate op");
-        ns.getOpValue();
+
+        assertThrows("Not an AnyUpdate op",
+                org.bitcoinj.script.ScriptException.class,
+                () -> ns.getOpValue());
     }
-    
+
     // TODO: getOpRand, getOpHash, isNameScript when they're implemented
-    
+
     NameScript getNameNewNameScript() throws IOException {
         byte[] payload;
         final Transaction tx;
         final TransactionOutput out;
         final Script outScript;
         final NameScript ns;
-        
+
         // https://namecoin.webbtc.com/tx/6047ce28a076118403aa960909c9c4d0056f97ee0da4d37d109515f8367e2ccb
-        
+
         payload = Util.getBytes(getClass().getResourceAsStream("namecoin_name_new_d_bitcoin.bin"));
         tx = new Transaction(params, payload);
         out = tx.getOutputs().get(1);
         outScript = out.getScriptPubKey();
         ns = new NameScript(outScript);
-        
+
         return ns;
     }
-    
+
     NameScript getNameFirstUpdateNameScript() throws IOException {
         byte[] payload;
         final Transaction tx;
         final TransactionOutput out;
         final Script outScript;
         final NameScript ns;
-        
+
         // https://namecoin.webbtc.com/tx/ab1207bd605af57ed0b5325ac94d19578cff3bce668ebe8dda2f42a00b001f5d
-        
+
         payload = Util.getBytes(getClass().getResourceAsStream("namecoin_name_firstupdate_d_bitcoin.bin"));
         tx = new Transaction(params, payload);
         out = tx.getOutputs().get(1);
         outScript = out.getScriptPubKey();
         ns = new NameScript(outScript);
-        
+
         return ns;
     }
-    
+
     NameScript getNameUpdateNameScript() throws IOException {
         byte[] payload;
         final Transaction tx;
         final TransactionOutput out;
         final Script outScript;
         final NameScript ns;
-        
+
         // https://namecoin.webbtc.com/tx/3376c5e0e5b69d0a104863de8432d7c13f891065e7628a72487b770c6418d397
-        
+
         payload = Util.getBytes(getClass().getResourceAsStream("namecoin_name_update_d_bitcoin.bin"));
         tx = new Transaction(params, payload);
         out = tx.getOutputs().get(1);
         outScript = out.getScriptPubKey();
         ns = new NameScript(outScript);
-        
+
         return ns;
     }
-    
+
     NameScript getCurrencyNameScript() throws IOException {
         byte[] payload;
         final Transaction tx;
         final TransactionOutput out;
         final Script outScript;
         final NameScript ns;
-        
+
         // https://namecoin.webbtc.com/tx/4ea5d679d63ef46449a44ca056584a986412676641bdaf13d44a7c7c2e32cca1
-        
+
         payload = Util.getBytes(getClass().getResourceAsStream("namecoin_p2pkh.bin"));
         tx = new Transaction(params, payload);
         out = tx.getOutputs().get(0);
         outScript = out.getScriptPubKey();
         ns = new NameScript(outScript);
-        
+
         return ns;
     }
-    
+
     NameScript getReturnNameScript() throws IOException {
         byte[] payload;
         final Transaction tx;
         final TransactionOutput out;
         final Script outScript;
         final NameScript ns;
-        
+
         // https://namecoin.webbtc.com/tx/ab1207bd605af57ed0b5325ac94d19578cff3bce668ebe8dda2f42a00b001f5d
-        
+
         payload = Util.getBytes(getClass().getResourceAsStream("namecoin_name_firstupdate_d_bitcoin.bin"));
         tx = new Transaction(params, payload);
         out = tx.getOutputs().get(2);
         outScript = out.getScriptPubKey();
         ns = new NameScript(outScript);
-        
+
         return ns;
     }
 }
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index 4d9ca1649..442d9132e 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.7.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.8.3-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/gradlew b/gradlew
old mode 100644
new mode 100755
diff --git a/namecoin/build.gradle b/namecoin/build.gradle
index 9cfa1d431..f1057562c 100644
--- a/namecoin/build.gradle
+++ b/namecoin/build.gradle
@@ -1,12 +1,16 @@
-apply plugin: 'java'
+apply plugin: 'java-library'
 
 dependencies {
     implementation project(':core')
-    implementation 'com.google.guava:guava:24.0-android'
+    implementation 'org.bitcoinj:bitcoinj-core:0.15.10'
+    implementation 'com.google.guava:guava:30.0-android'
     implementation 'net.sf.jopt-simple:jopt-simple:4.3'
-    implementation 'org.slf4j:slf4j-jdk14:1.7.25'
+    implementation 'org.slf4j:slf4j-api:1.7.30'
     implementation 'org.fusesource.leveldbjni:leveldbjni-all:1.8'
     implementation 'com.fasterxml.jackson.core:jackson-databind:2.5.2'
 }
 
 sourceCompatibility = 1.8
+
+test {
+}
\ No newline at end of file