synchronized

http://tutorials.jenkov.com/java-concurrency/synchronized.html

// instance methods (one thread per instance)

public synchronized void add(int value) {

this.count += value;

}

// code blocks inside instance methods

public void add(int value) {

synchronized (this) {

this.count += value;

}

}

// static methods (one thread per class)

public static synchronized void add(int value) {

count += value;

}

// code blocks inside static blocks

public static void add(int value) {

synchronized (MyClass.class) {

count += value;

}

}

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아래 1, 2번은 동일한 내용

1. public synchronized void methodA() {}

2. public void methodA() { synchronized (this) {} }

아래 3, 4번은 동일한 내용

3. public static synchronized void methodA() {}

4. public static void methodA() { synchronized (getClass()) {} }