我们知道JVM中一个对象实例超出作用域或无引用的时候会被垃圾回收，那么他被垃圾回收后，依赖其成员变量的其他实例是否还能正常使用呢？经过测试后发现即使一个实例被垃圾回收，如果他内部的数据被其他对象使用，是不受影响的，下面看这个示例
package test;
public class mytest {
public static void main(String[] args) throws Exception {
HandleBuffer hb = null;
{
Buffer buf = new Buffer();
hb = new HandleBuffer(buf.getBuf());
buf = null;
}
System.out.println("Has Buffer gone away?");
System.in.read();
Runtime.getRuntime().gc();
System.out.println("first gc finished!");
System.in.read();
System.out.println("Has Buffer gone away?");
Thread.currentThread().sleep(1000);
System.out.println(hb);
System.in.read();
}
}
class Buffer{
private byte[] buf = new byte[1024];
public Buffer(){
this.buf = "abc".getBytes();
}
public byte[] getBuf(){
return this.buf;
}
@Override
protected void finalize() throws Throwable {
System.out.println("Buffer gone away!");
}
}
class HandleBuffer{
byte[] buf = null;
public HandleBuffer(byte[] buf){
this.buf = buf;
}
@Override
public String toString() {
return new String(buf);
}
}
下面为程序运行输出：
Has Buffer gone away?
first gc finished!
Has Buffer gone away?
Buffer gone away! //此时对象已被垃圾回收
abc //访问数据正常
)
