在我的项目中使用 jar 时出错

我使用 Java 1.8 来创建我的 jar。

我在Java项目中可以使用它，但是在Android项目中，出现以下错误：

Error:Error converting bytecode to dex:
Cause: Dex cannot parse version 52 byte code.
This is caused by library dependencies that have been compiled using Java 8 or above.
If you are using the 'java' gradle plugin in a library submodule add 
targetCompatibility = '1.7'
sourceCompatibility = '1.7'
to that submodule's build.gradle file.
Error:1 error; aborting
Error:Execution failed for task ':app:transformClassesWithDexForDebug'.
> com.android.build.api.transform.TransformException: java.lang.RuntimeException: com.android.ide.common.process.ProcessException: java.util.concurrent.ExecutionException: com.android.ide.common.process.ProcessException: org.gradle.process.internal.ExecException: Process 'command 'E:\Android-tool\JAVA\jdk1.8.0_77\bin\java.exe'' finished with non-zero exit value 1
Information:BUILD FAILED
Information:Total time: 6.468 secs
Information:3 errors
Information:0 warnings
Information:See complete output in console

将这些东西添加到模块的build.gradle:

android {
    buildToolsVersion "24rc4"

    defaultConfig {
        jackOptions {
            enabled true
        }
    }
    dexOptions {
        incremental true
    }

    compileOptions {
        sourceCompatibility = org.gradle.api.JavaVersion.VERSION_1_8
        targetCompatibility = org.gradle.api.JavaVersion.VERSION_1_8
    }
}