E rror:Execution failed for task ‘: app:preDexDebug ‘.

> com.android.ide.common.process.ProcessException: org.gradle.process.internal.ExecException: Process ‘command ‘C:\Program Files\Java\jdk1.8.0_ 51\bin\java.exe” finished with non-zero exit value 1

This is caused by a duplicate jar package during compilation

Or your jar package and the system default are repeated. Delete the jar package one by one and debug it