I already know that question has been already asked very often and answers, but no one of the answers i found fixed my problem.
It's the error:
Error:Gradle: Execution failed for task ':ffcommunity:preDexDebug'. com.android.ide.common.internal.LoggedErrorException: Failed to run command: D:\Android SDK\sdk\build-tools\20.0.0\dx.bat --dex --output D:\Users\ReVo\Documents\IntelliJ IDEA\FFCommunity\ffcommunity\build\intermediates\pre-dexed\debug\bananaquery-2ee85432877a057e7414910b8127805535139d5d.jar D:\Users\ReVo\Documents\IntelliJ IDEA\FFCommunity\ffcommunity\libs\bananaquery.jar Error Code: 1 Output: UNEXPECTED TOP-LEVEL EXCEPTION: com.android.dx.cf.iface.ParseException: bad class file magic (cafebabe) or version (0034.0000) at com.android.dx.cf.direct.DirectClassFile.parse0(DirectClassFile.java:472) at com.android.dx.cf.direct.DirectClassFile.parse(DirectClassFile.java:406) at com.android.dx.cf.direct.DirectClassFile.parseToInterfacesIfNecessary(DirectClassFile.java:388) at com.android.dx.cf.direct.DirectClassFile.getMagic(DirectClassFile.java:251) at com.android.dx.command.dexer.Main.processClass(Main.java:665) at com.android.dx.command.dexer.Main.processFileBytes(Main.java:634) at com.android.dx.command.dexer.Main.access$600(Main.java:78) at com.android.dx.command.dexer.Main$1.processFileBytes(Main.java:572) at com.android.dx.cf.direct.ClassPathOpener.processArchive(ClassPathOpener.java:284) at com.android.dx.cf.direct.ClassPathOpener.processOne(ClassPathOpener.java:166) at com.android.dx.cf.direct.ClassPathOpener.process(ClassPathOpener.java:144) at com.android.dx.command.dexer.Main.processOne(Main.java:596) at com.android.dx.command.dexer.Main.processAllFiles(Main.java:498) at com.android.dx.command.dexer.Main.runMonoDex(Main.java:264) at com.android.dx.command.dexer.Main.run(Main.java:230) at com.android.dx.command.dexer.Main.main(Main.java:199) at com.android.dx.command.Main.main(Main.java:103) ...while parsing com/comuf/revonline/bananaquery/BananaInsert.class 1 error; aborting The error is bad class file magic (cafebabe) or version (0034.0000).
I builded and execute the application without problems many times in the same day but now this fails everytime with this message.
Project SDK is Android API 19 Platform and project level is 1.7.
CompileSDK is 19 and buildToolsVersion is '20.0.0'.
Compile options:
compileOptions { sourceCompatibility JavaVersion.VERSION_1_7 targetCompatibility JavaVersion.VERSION_1_7 } and in dependencies i have:
compile files('libs/bananaquery.jar') The library is build with SDK Android API 19 Platform with project level 1.7.
My .jar file is inside libs/ folder.
I use IntelliJ IDEA 14 Preview, it could be the reason? With IntellIJ IDEA 13 it remains stuck at "Gradle sync"
compile files could be useless since i have compile fileTree(dir: 'libs', include: ['*.jar']) too
my JAVA_HOME variable changed to Java 1.8 and I got this error message when compiling a pure java module as a dependency of my android project.
build.gradle of the java module
apply plugin: 'java' Solution #1: Quick an dirty
I fixed it by setting my JAVA_HOME back to 1.7:
export JAVA_HOME=`/usr/libexec/java_home -v 1.7` Solution #2: change compiler version:
change back to 1.7 for this specific module in its build.gradle
apply plugin: 'java' sourceCompatibility = 1.7 targetCompatibility = 1.7 Ok, my bad.
In the Project SDK section, when you add an Android SDK you should provide the Java SDK and all my Android SDKs uses Java 8 as SDK so it create the class files with the wrong version even if the Project level is 1.7 (i don't know why, i supposed that everything was choosed by Project level).
Now i changed the SDK (the java version "1.x.0" part.)
and it seems to compile fine.
The reason that worked before today was because my SDK was 1.8 and not Android API x
In case people find @Marco Acierno's answer to be a bit unclear, the solution is to ensure you're building with Java 7 and not a higher version.
For Android Studio, change File -> Project Structure -> SDK Location -> JDK Location to jdk1.7.x. For the command line, ensure java -version outputs java version "1.7.x".
Setting JAVA_HOME back to 1.7 worked for me.
change all your module java version to java 1.7 in every build.grade file.
in plugin which is library and application
compileOptions{ sourceCompatibility=JavaVersion.VERSION_1_7 targetCompatibility=JavaVersion.VERSION_1_7 } and in java
sourceCompatibility= 1.7 targetCompatibility= 1.7 This problem occurs when you use a .jar file that is not using any feature of Java 6 or higher but was built using Java 6 or higher.
If you built that .jar file then you don't need to change anything in Gradle or ProGuardor Compiler Version. The solution is very simple, just build that .jar file again but using Java 5 or less.
I had a similar issue, i solved it by upgrading my proguard. get your proguard version by this command
java -jar ~/android-sdks/tools/proguard/lib/proguard.jar get the latest progaurd.jar file from here (http://proguard.sourceforge.net)
replace the existing android-sdks/tools/proguard/lib/proguard.jar with new .jar file.
Hopefully this should help you. If u using java 8 then you should upgrade to proguard 5.x coz proguard 4.x does not support java 8.
had a similar issue when i tried to add a self made library from netbeans to android studio. setting the source- and target compatibility in android studio and source/binary format in netbeans (both!) to java 1.7 solved the problem.
in android studio:
Project Structure -> Modules/App -> Propreties -> Source- and Target to 1.7
in netbeans:
File -> Project Properties -> Sources -> Source/Binary Format to 1.7
then clean and build your netbeans projekt and copy the .jar from "NBProj/dist" to "app/libs"
share the solution of the case if only Java8 installed, just set Java compiler level to 1.7 and then rebuild the project should be OK.
来源：https://stackoverflow.com/questions/24662801/bad-class-file-magic-or-version