Java stack memory and heap memory

Java stack memory and heap memory
The stack memory stores local variables, and the heap memory stores objects. The class where the member variables are located is instantiated and stored in the heap memory. When the local variable method is called, it exists in the stack memory, and the referenced variable is also stored in the memory. A member variable is a class variable. class variables have initialization values and do not need to be defined. The setXXX and getXXX methods are generally required for class variables to provide external interfaces. Local variables must have initialization variable values.

Class Person {private int age; public void setAge (int a) {if (a> 0 & a <100) {age = a; speak ();} else System. out. println ("age input error");} public int getAge () {return age;} public void speak () {System. out. println ("Age:" + getAge () ;}} class PersonDemo {public static void main (String [] args) {Person p = new Person (); // p is the reference variable p. setAge (30); // p. getAge ();}}