// for check heap size
    public static void logHeap(Class clazz) {
     final int MEMORY_BUFFER_LIMIT_FOR_RESTART = 15;
        Double allocated = new Double(Debug.getNativeHeapAllocatedSize())/new Double((1048576));
        Double available = new Double(Debug.getNativeHeapSize())/new Double((1048576));
        Double free = new Double(Debug.getNativeHeapFreeSize())/new Double((1048576));
        DecimalFormat df = new DecimalFormat();
        df.setMaximumFractionDigits(2);
        df.setMinimumFractionDigits(2);
    
        Log.d("CWMusicPlayerUtil", "debug. =================================");
        Log.d("CWMusicPlayerUtil", "debug.heap native: allocated " + df.format(allocated) + "MB of " + df.format(available) + "MB (" + df.format(free) + "MB free) in [" + clazz.getName().replaceAll("com.asktingting.android.","") + "]");
        Log.d("CWMusicPlayerUtil", "debug.memory: allocated: " + df.format(new Double(Runtime.getRuntime().totalMemory()/1048576)) + "MB of " + df.format(new Double(Runtime.getRuntime().maxMemory()/1048576))+ "MB (" + df.format(new Double(Runtime.getRuntime().freeMemory()/1048576)) +"MB free)");
        System.gc();
    
        // don't need to add the following lines, it's just an app specific handling in my app
        /*
        if (allocated>=(new Double(Runtime.getRuntime().maxMemory())/new Double((1048576))-MEMORY_BUFFER_LIMIT_FOR_RESTART)) {
            android.os.Process.killProcess(android.os.Process.myPid());
        }
        */
    }