关于Android Error:Execution failed for task
':app:compileDebugJavaWithJavac'和
':app:transformJackWithJackForDebug'.
通过亲身受害，爬坑实践证明非常权威有效的解决方案
项目运行本身都是好好的，但就是那么突然，项目需要改一个地方，在发布的页面要修改之前的ui和功能，由之前只能打开相册选择一张照片变为用九宫格选择器形式选择多张图片并在页面中以九宫格形式显示出来图片并且每个图片右上角要带有删除的图标，可以进行删除操作，我第一反应是不难，因为之前做过一个类似的功能在自己的demo里面，可以直接导入作为一个mudule使用，于是点击AS的file-->new-->import mudule 选中依赖库导进来了项目中，本以为一切都非常顺利，结果问题出现了，编译之后报错了，红红的一大片，哈哈，由于太刺眼，下面就不贴成红色了，让程序员的大脑神经放松下吧，哈哈
org.gradle.api.tasks.TaskExecutionException: Execution failed for task ':app:compileDebugJavaWithJavac'. at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:100) at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.execute(ExecuteActionsTaskExecuter.java:70) at org.gradle.api.internal.tasks.execution.SkipUpToDateTaskExecuter.execute(SkipUpToDateTaskExecuter.java:63) at org.gradle.api.internal.tasks.execution.ResolveTaskOutputCachingStateExecuter.execute(ResolveTaskOutputCachingStateExecuter.java:54) at org.gradle.api.internal.tasks.execution.ValidatingTaskExecuter.execute(ValidatingTaskExecuter.java:58) at org.gradle.api.internal.tasks.execution.SkipEmptySourceFilesTaskExecuter.execute(SkipEmptySourceFilesTaskExecuter.java:88) at org.gradle.api.internal.tasks.execution.ResolveTaskArtifactStateTaskExecuter.execute(ResolveTaskArtifactStateTaskExecuter.java:52) at org.gradle.api.internal.tasks.execution.SkipTaskWithNoActionsExecuter.execute(SkipTaskWithNoActionsExecuter.java:52) at org.gradle.api.internal.tasks.execution.SkipOnlyIfTaskExecuter.execute(SkipOnlyIfTaskExecuter.java:54) at org.gradle.api.internal.tasks.execution.ExecuteAtMostOnceTaskExecuter.execute(ExecuteAtMostOnceTaskExecuter.java:43) at org.gradle.api.internal.tasks.execution.CatchExceptionTaskExecuter.execute(CatchExceptionTaskExecuter.java:34) at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker$1.run(DefaultTaskGraphExecuter.java:248) at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:336) at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:328) at org.gradle.internal.progress.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:197) at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:107) at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker.execute(DefaultTaskGraphExecuter.java:241) at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker.execute(DefaultTaskGraphExecuter.java:230) at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker.processTask(DefaultTaskPlanExecutor.java:124) at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker.access$200(DefaultTaskPlanExecutor.java:80) at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker$1.execute(DefaultTaskPlanExecutor.java:105) at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker$1.execute(DefaultTaskPlanExecutor.java:99) at org.gradle.execution.taskgraph.DefaultTaskExecutionPlan.execute(DefaultTaskExecutionPlan.java:625) at org.gradle.execution.taskgraph.DefaultTaskExecutionPlan.executeWithTask(DefaultTaskExecutionPlan.java:580) at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker.run(DefaultTaskPlanExecutor.java:99) at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:63) at org.gradle.internal.concurrent.ManagedExecutorImpl$1.run(ManagedExecutorImpl.java:46) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) at org.gradle.internal.concurrent.ThreadFactoryImpl$ManagedThreadRunnable.run(ThreadFactoryImpl.java:55) at java.lang.Thread.run(Thread.java:745) Caused by: org.gradle.api.internal.tasks.compile.CompilationFailedException: Compilation failed; see the compiler error output for details. at org.gradle.api.internal.tasks.compile.JdkJavaCompiler.execute(JdkJavaCompiler.java:51) at org.gradle.api.internal.tasks.compile.JdkJavaCompiler.execute(JdkJavaCompiler.java:36) at org.gradle.api.internal.tasks.compile.NormalizingJavaCompiler.delegateAndHandleErrors(NormalizingJavaCompiler.java:99) at org.gradle.api.internal.tasks.compile.NormalizingJavaCompiler.execute(NormalizingJavaCompiler.java:52) at org.gradle.api.internal.tasks.compile.NormalizingJavaCompiler.execute(NormalizingJavaCompiler.java:37) at org.gradle.api.internal.tasks.compile.CleaningJavaCompilerSupport.execute(CleaningJavaCompilerSupport.java:35) at org.gradle.api.internal.tasks.compile.CleaningJavaCompilerSupport.execute(CleaningJavaCompilerSupport.java:25) at org.gradle.api.tasks.compile.JavaCompile.performCompilation(JavaCompile.java:198) at org.gradle.api.tasks.compile.JavaCompile.compile(JavaCompile.java:183) at org.gradle.api.tasks.compile.JavaCompile.compile(JavaCompile.java:120) at com.android.build.gradle.tasks.factory.AndroidJavaCompile.compile(AndroidJavaCompile.java:49) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.gradle.internal.reflect.JavaMethod.invoke(JavaMethod.java:73) at org.gradle.api.internal.project.taskfactory.DefaultTaskClassInfoStore$IncrementalTaskAction.doExecute(DefaultTaskClassInfoStore.java:173) at org.gradle.api.internal.project.taskfactory.DefaultTaskClassInfoStore$StandardTaskAction.execute(DefaultTaskClassInfoStore.java:134) at org.gradle.api.internal.project.taskfactory.DefaultTaskClassInfoStore$StandardTaskAction.execute(DefaultTaskClassInfoStore.java:121) at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter$1.run(ExecuteActionsTaskExecuter.java:122) at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:336) at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:328) at org.gradle.internal.progress.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:197) at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:107) at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeAction(ExecuteActionsTaskExecuter.java:111) at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:92) ... 30 more
问题出现了，以前没有见过,二话不说，google搜索解决方案，有很多这样的博客，主要的解决方案有以下几种：
1.关闭增量编译，在bulide.gradle文件中android{ ... } 下compileOptions{}中加一行incremental = false
2.把项目中用到java8的方法等用java7的替换，还是回归java7；
3.Check build.gradle(Module: Android) fixed problem 升级build.gradle中的buildToolsVersion到最新的版本；
4.升级Android Studio的版本（Help->Check for Updates...） 以及 配置JAVA_HOME的路径；
5.移除jackOptions { enabled true }
和compileOptions {sourceCompatibility JavaVersion.VERSION_1_8
targetCompatibility JavaVersion.VERSION_1_8
incremental false
}
但是我挨个儿尝试后都不见效，依然无法解决，最后实在解决不了，只好回退老版本，重新来过，但依然卡在这个地方，头痛的要命，死命google，百度，死磕两天终于找到了解决方案，幸福来的就是这么突然，哈哈
原来 app:compileDebugJavaWithJavac 造成的原因是java jdk 8 编译的方式和之前版本的编译方式变了，所以代码里面有语法错误或者类路径错误会导致编译不能通过而报出这个异常，这里简单讲下新版和旧版的jdk的编译方式的区别。
- 旧版 javac 工具链：
javac (.java –> .class) –> dx (.class –> .dex) - 新版 Jack 工具链：
Jack (.java –> .jack –> .dex)
回到正题上，真正的解决方案在这里，非常神奇：
在命令行中进入项目的根目录，或者可以在Android studio的Terminal中直接操作也可以，然后敲入一个命令：
gradlew compileDebug --stacktrace -info
或者：
gradlew compileDebug --stacktrace -debug
我直接用了这个命令，这个显示的错误信息最详细，建议你直接用这个，
gradlew compileDebugSources --stacktrace -info -debug的命令我也试了，显示的非常多，但不像-info一样显示错误提示的信息非常详细，你可以两个都尝试一下。
最后在出现的信息中找到了这个提示
于是顺着错误提示的地方果然找到了，原来是类的导入路径错误引起的这个异常，解决掉这个错误后再次编译眼睛盯着编译的进度，最担心突然tasks停下来爆出一片红了，I am so lucky!!!,项目成功的跑起来了，哈哈，开眼界了这一次，祝贺自己能从这个大坑里面爬出来吧，哈哈，顺便写下这篇博客来记录这一段爬坑的“美好”记忆
，也作为以后再遇到此类问题的经验