Cannot build with Java 1.8

[ekchang]

Not sure if this is known, but installing Rebound using JDK 1.8u25 fails (both Playground and Example). It's weird because Gradle says the build succeeds until I try to push it to a device. JDK 1.7u75 has no issues, so I'm not too sure exactly what's going on. I don't see any specific build.gradle or settings.gradle files which specify a JDK version to build with either.

Error occurs during preDexDebug:

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/facebook/rebound/BaseSpringSystem.class

[willbailey]

Can you try adding the following to your build.gradle? I haven't attempted to build with 1.8 as it's not supported for Android yet to my knowledge.

compileOptions {
targetCompatibility JavaVersion.VERSION_1_7
}

[ekchang]

Looking deeper, you're right - 1.8 isn't officially supported for Android, only 1.6. The error (bad class file magic (cafebabe) or version (0034.0000)" refers to a mismatch between a library compiled in a version that isn't the SDK version (0034 refers to Java 1.8).

Adding the compile options to change target compatibility still doesn't work, but it's fine. The correct resolution is to just not compile with 1.8 at all.