Advantages of synchronized statement over synchronized methods

- can be smaller than a method (can be inside a unsynchronized method), allows holding locks for a smaller time and i.e. to protect only a single field assignment .

- allow to synchronize on other objects than this



Example :



class separateGroups {

private double aVal = 0.0;

private double bVal = 1.1;

protected Object lockA = new Object();

protected Object lockB = new Object();



public double getA(){

synchronized (lockA){

return aVal;

}

}



public void setA(double val){

synchronized (lockA){

aVal=val;

}

}



public double getB(){

synchronized (lockB){

return bVal;

}

}





public void setB(double val){

synchronized (lockB){

bVal=val;

}

}





public void reset(){

synchronized (lockA){

synchronized (lockB){

aVal=bval=0.0;

}

}

}



the reset method changes both values therefore it acquires both locks.