创建一个同步Map

import java.util.Collections;
import java.util.HashMap;
import java.util.Map;

public class GreateSynchronizedMap {

public static void main(String[] args) {
    // TODO Auto-generated method stub
    System.out.println(synchronizedMap());
}

public static <K, V> Map<K, V> synchronizedMap() {
    return Collections.synchronizedMap(new HashMap<K, V>());
}

public static <K, V> Map<K, V> synchronizedMap(final int initialCapacity) {
    return Collections.synchronizedMap(new HashMap<K, V>(
            initialCapacity));
}

protected static <K, V> Map<K, V> synchronizedMap(
        final int initialCapacity, final float loadFactor) {
    return Collections.synchronizedMap(new HashMap<K, V>(
            initialCapacity, loadFactor));
}

}
Console：
{}