Apply kotlin plugin and convert one unused class to kotlin

just to check that everything works and to show how much simpler
kotlin code looks.

build.gradle

@@ -8,6 +8,7 @@ buildscript {
         classpath 'com.github.jengelman.gradle.plugins:shadow:4.0.2'
         classpath files('gradle/witness/gradle-witness.jar')
         classpath 'org.springframework.boot:spring-boot-gradle-plugin:1.5.10.RELEASE'
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:1.3.41"
     }
 }
 
@@ -21,6 +22,7 @@ configure(rootProject) {
 }
 
 configure(subprojects) {
+    apply plugin: 'kotlin'
     apply plugin: 'java'
     apply plugin: 'com.google.osdetector'
 
@@ -173,6 +175,7 @@ configure(project(':common')) {
     }
 
     dependencies {
+        implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.3.41"
         compile "org.openjfx:javafx-base:11:$os"
         compile "org.openjfx:javafx-graphics:11:$os"
         compile "com.google.protobuf:protobuf-java:$protobufVersion"

gradle/witness/gradle-witness.gradle

@@ -45,10 +45,10 @@ dependencyVerification {
         'com.google.inject:guice:d258ff1bd9b8b527872f8402648226658ad3149f1f40e74b0566d69e7e042fbc',
         'com.github.bisq-network.bitcoinj:bitcoinj-core:f979c2187e61ee3b08dd4cbfc49a149734cff64c045d29ed112f2e12f34068a3',
         'com.github.JesusMcCloud.netlayer:tor:7950f8b44609eba2524941cb6517f43ade34e53c820aea849006e22eee93a83d',
-        'org.jetbrains.kotlin:kotlin-stdlib-jdk8:193ab7813e4d249f2ea4fc1b968fea8c2126bcbeeb5d6127050ce1b93dbaa7c2',
+        'org.jetbrains.kotlin:kotlin-stdlib-jdk8:f7dbbaee3e0841758187a213c052388a4e619e11c87ab16f4bc229cfe7ce5fed',
         'io.github.microutils:kotlin-logging:4992504fd3c6ecdf9ed10874b9508e758bb908af9e9d7af19a61e9afb6b7e27a',
-        'org.jetbrains.kotlin:kotlin-stdlib-jdk7:877b59bbe466b24a88275a71fd06cd97359d2085420f6f1ac1d766afa8116001',
-        'org.jetbrains.kotlin:kotlin-stdlib:4ff0fcb97f4983b4aaba12668c24ad21b08460915db1b021d8f1d8bee687f21c',
+        'org.jetbrains.kotlin:kotlin-stdlib-jdk7:25e2409aba0ec37d2fd7c77727d7835b511879de8d9bf4862af0b493aabbe39e',
+        'org.jetbrains.kotlin:kotlin-stdlib:6ea3d0921b26919b286f05cbdb906266666a36f9a7c096197114f7495708ffbc',
         'org.jetbrains:annotations:ace2a10dc8e2d5fd34925ecac03e4988b2c0f851650c94b8cef49ba1bd111478',
         'org.bouncycastle:bcpg-jdk15on:de3355b821fc81dd32e1f3f560d5b3eca1c678fd2400011d0bfc69fb91bcde85',
         'commons-io:commons-io:cc6a41dc3eaacc9e440a6bd0d2890b20d36b4ee408fe2d67122f328bb6e01581',
@@ -77,6 +77,6 @@ dependencyVerification {
         'org.apache.commons:commons-compress:5f2df1e467825e4cac5996d44890c4201c000b43c0b23cffc0782d28a0beb9b0',
         'org.tukaani:xz:a594643d73cc01928cf6ca5ce100e094ea9d73af760a5d4fb6b75fa673ecec96',
         'com.squareup.okio:okio:114bdc1f47338a68bcbc95abf2f5cdc72beeec91812f2fcd7b521c1937876266',
-        'org.jetbrains.kotlin:kotlin-stdlib-common:4b161ef619eee0d1a49b1c4f0c4a8e46f4e342573efd8e0106a765f47475fe39',
+        'org.jetbrains.kotlin:kotlin-stdlib-common:6c91dea17d7dce5f0b550c3de3305767e5fb46247b6d1eb7eca0ca1fe18458de',
     ]
 }

p2p/src/test/java/bisq/network/p2p/storage/ProtectedDataStorageTest.java

@@ -149,7 +149,7 @@ public void testAddAndRemove() throws InterruptedException, NoSuchAlgorithmExcep
 
     // @Test
     public void testTTL() throws InterruptedException, NoSuchAlgorithmException, CertificateException, KeyStoreException, IOException, CryptoException, SignatureException, InvalidKeyException, NoSuchProviderException {
-        mockData.ttl = (int) (P2PDataStorage.CHECK_TTL_INTERVAL_SEC * 1.5);
+        mockData.setTtl((int) (P2PDataStorage.CHECK_TTL_INTERVAL_SEC * 1.5));
         ProtectedStorageEntry data = dataStorage1.getProtectedStorageEntry(mockData, storageSignatureKeyPair1);
         log.debug("data.date " + data.getCreationTimeStamp());
         Assert.assertTrue(dataStorage1.addProtectedStorageEntry(data, null, null, true));
@@ -198,7 +198,7 @@ public void testRePublish() throws InterruptedException, NoSuchAlgorithmExceptio
  */
     @Test
     public void testRefreshTTL() throws InterruptedException, NoSuchAlgorithmException, CertificateException, KeyStoreException, IOException, CryptoException, SignatureException, InvalidKeyException, NoSuchProviderException {
-        mockData.ttl = (int) (P2PDataStorage.CHECK_TTL_INTERVAL_SEC * 1.5);
+        mockData.setTtl((int) (P2PDataStorage.CHECK_TTL_INTERVAL_SEC * 1.5));
         ProtectedStorageEntry data = dataStorage1.getProtectedStorageEntry(mockData, storageSignatureKeyPair1);
         Assert.assertTrue(dataStorage1.addProtectedStorageEntry(data, null, null, true));
         Assert.assertEquals(1, dataStorage1.getMap().size());

p2p/src/test/java/bisq/network/p2p/storage/mocks/MockData.kt

@@ -0,0 +1,39 @@
+/*
+ * This file is part of Bisq.
+ *
+ * Bisq is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or (at
+ * your option) any later version.
+ *
+ * Bisq is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public
+ * License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with Bisq. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package bisq.network.p2p.storage.mocks
+
+import bisq.network.p2p.storage.payload.ExpirablePayload
+import bisq.network.p2p.storage.payload.ProtectedStoragePayload
+
+import org.apache.commons.lang3.NotImplementedException
+
+import java.security.PublicKey
+
+data class MockData(val msg: String?, val publicKey: PublicKey) : ProtectedStoragePayload, ExpirablePayload {
+    var ttl: Long = 0
+    override fun getOwnerPubKey(): PublicKey = publicKey
+
+
+    override fun getExtraDataMap(): Map<String, String>? = null
+
+    override fun getTTL(): Long = ttl
+
+    override fun toProtoMessage(): protobuf.ProtectedMailboxStorageEntry {
+        throw NotImplementedException("toProtoMessage not impl.")
+    }
+}