Android build fixes.

ethereumj-core-android/build.gradle

@@ -38,7 +38,14 @@ android {
 dependencies {
     apt 'com.google.dagger:dagger-compiler:2.0'
     compile fileTree(dir: 'libs', include: ['*.jar'])
-    compile project(':ethereumj-core')
+    compile (project(':ethereumj-core')) {
+        exclude group: "org.apache.commons", module: "commons-pool2"
+        exclude group: "org.slf4j", module: "slf4j-log4j12"
+        exclude group: "org.hibernate", module: "hibernate-core"
+        exclude group: "org.hibernate", module: "hibernate-entitymanager"
+        exclude group: "redis.clients", module: "jedis"
+
+    }
 
     compile "com.google.dagger:dagger:2.1-SNAPSHOT"
     compile "com.j256.ormlite:ormlite-android:4.48"

ethereumj-core/build.gradle

@@ -1,5 +1,3 @@
-//apply plugin: 'com.android.library'
-//apply plugin: 'com.neenbedankt.android-apt'
 
 buildscript {
     repositories {
@@ -12,7 +10,6 @@ buildscript {
     dependencies {
         classpath 'me.champeau.gradle:antlr4-gradle-plugin:0.1'
         classpath 'org.jfrog.buildinfo:build-info-extractor-gradle:3.0.1'
-//        classpath 'com.neenbedankt.gradle.plugins:android-apt:1.4'
     }
 }
 
@@ -51,7 +48,21 @@ antlr4 {
     output = file("${generatedSrcDir}/org/ethereum/serpent")
 }
 
-preBuild.dependsOn antlr4
+if (isJavaProject(project)) {
+    compileJava.dependsOn antlr4
+} else if (isAndroidProject(project)) {
+    preBuild.dependsOn antlr4
+} else {
+    throw new GradleException('unknown plugin type')
+}
+
+public static boolean isJavaProject(Project project) {
+    project.plugins.findPlugin('java')
+}
+public static boolean isAndroidProject(Project project) {
+    project.plugins.findPlugin('com.android.application') || project.plugins.findPlugin('com.android.library')
+}
+
 
 
 ext {
@@ -82,7 +93,6 @@ dependencies {
     compile 'com.google.dagger:dagger-compiler:2.0'
     compile 'com.google.dagger:dagger:2.0'
     compile fileTree(include: ['*.jar'], dir: 'libs')
-    //provided 'javax.annotation:javax.annotation-api:1.2'
 
     compile('io.netty:netty-all:4.0.28.Final') {
         exclude group: 'commons-logging', module: 'commons-logging'
@@ -110,15 +120,10 @@ dependencies {
     compile 'org.apache.commons:commons-collections4:4.0'
     compile "commons-codec:commons-codec:1.10"
     compile 'org.hsqldb:hsqldb:1.8.0.10' // best performance - do not upgrade!
-    compile ("org.hibernate:hibernate-core:${hibernateVersion}") {
-        exclude group: 'commons-logging', module: 'commons-logging'
-    }
+    compile "org.hibernate:hibernate-core:${hibernateVersion}"
     compile "org.hibernate:hibernate-entitymanager:${hibernateVersion}"
 
-
-    compile('redis.clients:jedis:2.6.0') {
-        exclude group: 'org.apache.commons', module: 'commons-pool2'
-    }
+    compile "redis.clients:jedis:2.6.0"
     compile('com.googlecode.json-simple:json-simple:1.1.1') {
         exclude group: 'junit', module: 'junit'
         exclude group: 'xml-apis', module: 'xml-apis'

ethereumj-core/src/main/java/org/ethereum/datasource/redis/RedisConnectionImpl.java

@@ -59,7 +59,6 @@ public class RedisConnectionImpl implements RedisConnection {
                 redisUri.getHost(),
                 redisUri.getPort(),
                 Protocol.DEFAULT_TIMEOUT);
-        return null;
     }
 
     @PreDestroy