libgdx - Android: UNEXPECTED TOP-LEVEL EXCEPTION -

libgdx - Android: UNEXPECTED TOP-LEVEL EXCEPTION -

i got error while compiling libgdx project gradle.

execution failed task ':android:predexamazondebug'. > com.android.ide.common.internal.loggederrorexception: failed run command: /sdk-path/android/build-tools/21.0.1/dx --dex --output /path/android/build/intermediates/pre-dexed/amazon/debug/core-1.0-47e2423a0159bad5774996683a8ab834009ab7ed.jar /path/core/build/libs/core-1.0.jar error code: 1 output: unexpected top-level exception: com.android.dx.cf.iface.parseexception: bad class file magic (cafebabe) or version (0034.0000) @ com.android.dx.cf.direct.directclassfile.parse0(directclassfile.java:472) @ com.android.dx.cf.direct.directclassfile.parse(directclassfile.java:406) @ com.android.dx.cf.direct.directclassfile.parsetointerfacesifnecessary(directclassfile.java:388) @ com.android.dx.cf.direct.directclassfile.getmagic(directclassfile.java:251) @ com.android.dx.command.dexer.main.processclass(main.java:704) @ com.android.dx.command.dexer.main.processfilebytes(main.java:673) @ com.android.dx.command.dexer.main.access$300(main.java:82) @ com.android.dx.command.dexer.main$1.processfilebytes(main.java:602) @ com.android.dx.cf.direct.classpathopener.processarchive(classpathopener.java:284) @ com.android.dx.cf.direct.classpathopener.processone(classpathopener.java:166) @ com.android.dx.cf.direct.classpathopener.process(classpathopener.java:144) @ com.android.dx.command.dexer.main.processone(main.java:632) @ com.android.dx.command.dexer.main.processallfiles(main.java:510) @ com.android.dx.command.dexer.main.runmonodex(main.java:279) @ com.android.dx.command.dexer.main.run(main.java:245) @ com.android.dx.command.dexer.main.main(main.java:214) @ com.android.dx.command.main.main(main.java:106) ...while parsing org/mars3142/ownclass.class 1 error; aborting

i didn't include core twice android project. double checked, if include external libs, seems, own project failure, can't understand, because never changed something. added android-wear project project. , if go time (with git), not compileable.

edit: if nail run in intellij same build variant (amazondebug) works expected. that's strange.

android libgdx android-gradle