靜態方法是在new之前就已經載入到記憶體地址中了，再次new物件時候這些靜態屬性或者靜態方法不會再分配新的記憶體地址了，這些靜態屬性或者靜態方法在多個物件中是共用的。

public class Common {
	private static	String test = "123";
	private	String test1 = "456";
	
	public static String getTest() {
		return test;
	}

	public static void setTest(String test) {
		Common.test = test;
	}

	public String getTest1() {
		return test1;
	}

	public void setTest1(String test1) {
		this.test1 = test1;
	}
}
/*************test*************/
System.out.println("Common test = "+Common.getTest());
Common.setTest("abc");
System.out.println("Common test = "+Common.getTest());

Common com = new Common();
Common com1 = new Common();
System.out.println("------------------------------");
System.out.println("com test = "+com.getTest());
System.out.println("com1 test = "+com1.getTest());
System.out.println("com test1 = "+com.getTest1());
System.out.println("com1 test1 = "+com1.getTest1());
com.setTest("cccccccccc");
com.setTest1("dddddddddd");
System.out.println("------------------------------");
System.out.println("com test = "+com.getTest());
System.out.println("com1 test = "+com1.getTest());
System.out.println("com test1 = "+com.getTest1());
System.out.println("com1 test1 = "+com1.getTest1());
System.out.println("Common test = "+Common.getTest());
 

Common test = 123
Common test = abc
------------------------------
com test = abc
com1 test = abc
com test1 = 456
com1 test1 = 456
------------------------------
com test = cccccccccc
com1 test = cccccccccc
com test1 = dddddddddd
com1 test1 = 456
Common test = cccccccccc