title: Error:Execution failed for task ':app:transformClassesWithDexForDebug'
body: <p>While I searched the error message, I got many smaller questions but none of them help me. So I am asking it again. For me, this error happens while I am adding a Handler to update my UI. If I remove the handler there will be no error. Why is it happen. </p>
  
  <p><a href="https://i.stack.imgur.com/5Oz2E.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/5Oz2E.png" alt="Error:Execution failed for task &#39;:app:transformClassesWithDexForDebug&#39;."></a> </p>
  
  <pre><code>    com.android.build.api.transform.TransformException:  
      com.android.ide.common.process.ProcessException:                
      org.gradle.process.internal.ExecException: Process 
      'command 'C:\Program Files\Java\jdk1.8.0_60\bin\java.exe''
      finished with non-zero exit value 2
  </code></pre>
  
  <p>check my gradle. </p>
  
  <pre><code> apply plugin: 'com.android.application'
  
  android {
  compileSdkVersion 23
  buildToolsVersion "23.0.1"
  
  defaultConfig {
      applicationId "com.medical.trofii"
      minSdkVersion 15
      targetSdkVersion 23
      versionCode 1
      versionName "1.0"
      packagingOptions {
          exclude 'META-INF/DEPENDENCIES'
          exclude 'META-INF/NOTICE'
          exclude 'META-INF/LICENSE'
      }
  }
  buildTypes {
      release {
          minifyEnabled false
          proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
      }
  }
  }
  
  dependencies {
  compile fileTree(dir: 'libs', include: ['*.jar'])
  testCompile 'junit:junit:4.12'
  compile group: 'cz.msebera.android', name: 'httpclient', version: '4.4.1.1'
  compile project(':rangeseekbar')
  compile project(':library')
  
  
  compile 'com.android.support:appcompat-v7:23.1.1'
  compile 'it.dex.dexmovingimageview:dexmovingimageviewlib:0.1.0'
  compile 'com.google.android.gms:play-services:8.3.0'
  compile 'com.android.support:design:23.1.1'
  compile 'com.android.support:support-v4:23.1.1'
  compile 'com.github.rahatarmanahmed:circularprogressview:2.4.0'
  compile 'com.github.traex.rippleeffect:library:1.3'
  compile 'com.mcxiaoke.volley:library-aar:1.0.0'
  compile 'cn.pedant.sweetalert:library:1.3'
  compile 'com.mikhaellopez:circularimageview:2.1.1'
  </code></pre>
  
  <p>}</p>