Error:Unable to load class
‘com.android.build.gradle.internal.tasks.OutputFileTask’. Possible
causes for this unexpected error include:

• Gradle’s dependency
  cache may be corrupt (this sometimes occurs after a network connection
  timeout.) Re-download dependencies and sync
  project (requires network)
• The state of a Gradle build
  process (daemon) may be corrupt. Stopping all Gradle daemons may solve
  this problem. Stop Gradle build processes
  (requires restart)

In the case of corrupt Gradle
processes,you can also try closing the IDE and then killing all Java
processes.

这是我的gradle文件

apply plugin: 'com.android.library'
apply plugin: 'maven'
apply plugin: 'maven-publish'

android {
    compileSdkVersion 21
    buildToolsVersion "21.1.2"

    repositories {
        mavenCentral()
    }

    defaultConfig {
        minSdkVersion 9
        targetSdkVersion 21
        versionCode 1
        versionName "1.0"
    }
    buildTypes {
        release {
            minifyEnabled false
            consumerProguardFiles getDefaultProguardFile('proguard-android.txt'),'proguard-rules.pro'
        }
    }

    lintOptions {
        abortOnError false
        checkReleaseBuilds false
    }

    packagingOptions {
        exclude 'Meta-INF/services/javax.annotation.processing.Processor'
        exclude 'Meta-INF/DEPENDENCIES.txt'
        exclude 'Meta-INF/DEPENDENCIES'
        exclude 'Meta-INF/LICENSE.txt'
        exclude 'Meta-INF/LICENSE'
        exclude 'Meta-INF/NOTICE.txt'
        exclude 'Meta-INF/NOTICE'
        exclude 'Meta-INF/LGPL2.1'
    }
}


dependencies {
    compile 'com.android.support:support-v4:22.1.0'
    compile 'com.android.support:appcompat-v7:22.1.0'
}

task sourceJar(type: Jar) {
    classifier "source"
}



publishing {
    publications {

        repositories.maven {
            url repo
            credentials {
                username user
                password passwd
            }
        }

        maven(MavenPublication) {
            artifacts {
                groupId 'com.android'
                artifactId 'artefact-1'
                version '1'
                artifact artifactPath
            }
        }
    }

}

}

我认为可能还有另一个gradle api更改导致旧的东西不再工作.

如何解决问题再次构建我的项目？