}
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3、 编写一个延迟加载的单例设计模式。
public class Test3{
Single s = Single.getInstance();
}
class Single{
private Single() {
}
private static Single s = null;
public static Single getInstance() {
if (s == null)
s = new Single();
return s;
}
}
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7、 在打印语句中如何打印这3个x变量?
public class Test7 {
public static void main(String[] args) {
X xxx = new X();
X.Y y = xxx.new Y();
y.func();
}
}
class X {
int i = 1;
class Y {
int i = 2;
void func() {
int i = 3;
System.out.println(X.this.i);
System.out.println(this.i);
System.out.println(i);
}
}
}