目录一、jdk二、jre三、jvm四、关系图五、一个Java程序的执行过程总结一、jdk JDK（Java Development Kit）：
what is the nullable开发者_运维百科 integer and where can it be used?The nullable integer int? or Nullable<int> is a value type in C# whose value can be null or an integer value. It defaults to
加载中,请稍侯......