Revert introduction of Kotlin compilation to the build

.editorconfig

@@ -9,6 +9,9 @@ charset = utf-8
 trim_trailing_whitespace = true
 insert_final_newline = true
 
+[*.diff]
+trim_trailing_whitespace = false
+
 [Makefile]
 indent_style = tab
 

.gitignore

@@ -19,6 +19,7 @@ build
 .project
 .settings
 *.java.hsp
+*.java.hsw
 *.~ava
 /bundles
 /bisq-*

build.gradle

@@ -8,7 +8,6 @@ buildscript {
         classpath 'com.github.jengelman.gradle.plugins:shadow:5.2.0'
         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"
     }
 }
 
@@ -22,7 +21,6 @@ configure(rootProject) {
 }
 
 configure(subprojects) {
-    apply plugin: 'kotlin'
     apply plugin: 'java'
     apply plugin: 'com.google.osdetector'
 

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

@@ -0,0 +1,88 @@
+/*
+ * 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;
+
+import java.util.Map;
+
+import javax.annotation.Nullable;
+
+@SuppressWarnings("ALL")
+public class MockData implements ProtectedStoragePayload, ExpirablePayload {
+    public final String msg;
+    public final PublicKey publicKey;
+    public long ttl;
+
+    @Nullable
+    private Map<String, String> extraDataMap;
+
+    public MockData(String msg, PublicKey publicKey) {
+        this.msg = msg;
+        this.publicKey = publicKey;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (!(o instanceof MockData)) return false;
+
+        MockData that = (MockData) o;
+
+        return !(msg != null ? !msg.equals(that.msg) : that.msg != null);
+
+    }
+
+    @Override
+    public int hashCode() {
+        return msg != null ? msg.hashCode() : 0;
+    }
+
+    @Override
+    public String toString() {
+        return "MockData{" +
+                "msg='" + msg + '\'' +
+                '}';
+    }
+
+    @Nullable
+    @Override
+    public Map<String, String> getExtraDataMap() {
+        return extraDataMap;
+    }
+
+    @Override
+    public long getTTL() {
+        return ttl;
+    }
+
+    @Override
+    public PublicKey getOwnerPubKey() {
+        return publicKey;
+    }
+
+    @Override
+    public protobuf.ProtectedMailboxStorageEntry toProtoMessage() {
+        throw new NotImplementedException("toProtoMessage not impl.");
+    }
+}