[java-decompiler] migrates to Gradle

Simplifies CI (the outer IDEA project no longer bundles JUnit and AssertJ .jars).

.gitignore

@@ -0,0 +1,2 @@
+/.gradle/
+/build/

build.gradle

@@ -0,0 +1,24 @@
+apply plugin: 'java'
+
+compileJava {
+  sourceCompatibility '1.8'
+  targetCompatibility '1.8'
+}
+
+sourceSets {
+  main.java.srcDirs 'src'
+  test.java.srcDirs 'test'
+}
+
+repositories { jcenter() }
+dependencies {
+  testCompile 'junit:junit:4.+'
+  testCompile 'org.assertj:assertj-core:3.+'
+}
+
+jar {
+  archiveName 'fernflower.jar'
+  manifest {
+    attributes 'Main-Class': 'org.jetbrains.java.decompiler.main.decompiler.ConsoleDecompiler'
+  }
+}

build.xml

@@ -1,59 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project name="Fernflower" default="dist" basedir=".">
-
-  <target name="init">
-    <property name="src" value="${basedir}/src"/>
-    <property name="out" value="${basedir}/out/production"/>
-    <property name="dist" value="${basedir}/fernflower.jar"/>
-    <property name="test-src" value="${basedir}/test"/>
-    <property name="test-out" value="${basedir}/out/test"/>
-  </target>
-
-  <!-- external dependencies, adjust to your own -->
-  <path id="junit">
-    <file name="${basedir}/../../../lib/junit-4.12.jar"/>
-    <file name="${basedir}/../../../lib/hamcrest-core-1.3.jar"/>
-    <file name="${basedir}/../../../lib/dev/assertj-core-3.6.1.jar"/>
-  </path>
-
-  <target name="clean" depends="init">
-    <delete includeemptydirs="true" failonerror="false">
-      <fileset dir="${out}"/>
-      <fileset dir="${test-out}"/>
-      <fileset file="${dist}"/>
-    </delete>
-  </target>
-
-  <target name="compile" depends="init,clean">
-    <mkdir dir="${out}"/>
-    <javac srcdir="${src}" destdir="${out}" source="1.8" target="1.8" encoding="UTF-8" debug="true" includeantruntime="false"/>
-  </target>
-
-  <target name="dist" depends="init,compile">
-    <jar jarfile="${dist}" compress="true" basedir="${out}" includes="**/*.class">
-      <manifest>
-        <attribute name="Main-Class" value="org.jetbrains.java.decompiler.main.decompiler.ConsoleDecompiler"/>
-      </manifest>
-    </jar>
-  </target>
-
-  <target name="test-compile" depends="init,compile">
-    <mkdir dir="${test-out}"/>
-    <javac srcdir="${test-src}" destdir="${test-out}" source="1.8" target="1.8" encoding="UTF-8" debug="true" includeantruntime="false">
-      <classpath path="${out}"/>
-      <classpath refid="junit"/>
-    </javac>
-  </target>
-
-  <target name="test" depends="init,test-compile">
-    <junit printsummary="true" failureproperty="tests.failed" fork="true">
-      <classpath path="${test-out}:${out}"/>
-      <classpath refid="junit"/>
-      <batchtest>
-        <fileset dir="${test-src}" includes="**/*Test.java"/>
-      </batchtest>
-    </junit>
-    <fail if="tests.failed" message="Tests failed."/>
-  </target>
-
-</project>