question: private static DexClassLoader createInstance ( Configuration config ) { File file1 ; File file2 ; switch ( config ) { case ONE_DEX : file1 = DEX_FILE ; file2 = null ; break ; case ONE_JAR : file1 = JAR_FILE ; file2 = null ; break ; case TWO_DEX : file1 = DEX_FILE ; file2 = DEX2_FILE ; break ; case TWO_JAR : file1 = JAR_FILE ; file2 = JAR2_FILE ; break ; default : throw new AssertionError ( "shouldn't happen" ) ; } String path = file1 . getAbsolutePath ( ) ; if ( file2 != null ) { path += File . pathSeparator + file2 . getAbsolutePath ( ) ; } return new DexClassLoader ( path , OPTIMIZED_DIR . getAbsolutePath ( ) , null , ClassLoader . getSystemClassLoader ( ) ) ; }
target:  Helper to construct an instance to test.