java - 哪里需要同步？

Question

public class sample1
{
    private static Map m = new HashMap();
    //....
    //.....
    //
    public void fun(String str1, String str2, sample2 s )
    {
        String str = str1 + str2 + s.getName();
        String value = m.get(str);
    }
}

public class sample2
{
    private String name;
            // ......
            // ........
            pubic String getName()
             {
                  return name;
             }
}

在这里，我的问题是变量（函数 fun 的参数）如 str1、str2 和 s（sample2 对象）究竟存储在堆还是堆栈中？

Answer 1

You will never have any synchronization failure with str1 and str2, because those variables are strings, and the string class is immutable in Java.