java结果输出，知其所以然

代码输出结果是什么？为什么会出现这种结果？代码一public class ParentTest {public ParentTest(){System.out.println("Parent Constructor invoked");}static{System.out.println("parent static invoked");}{System.out.println("parent invoked");}}public class ChildrenTest extends ParentTest{public ChildrenTest(){System.out.println("Children Constructor invoked");}static{System.out.println("Children static invoked");}{System.out.println("Children invoked");}public static void main(String[] args) {new ChildrenTest();}}代码二:true or falsepublic class MyTest1 {private String str;public MyTest1(String str){this.str=str;}public static void main(String[] args) {MyTest1 m1=new MyTest1("hello");MyTest1 m2=new MyTest1("hello");System.out.println(m1.equals(m2));}}代码三:true or falsepublic class MyTest1 {public static void main(String[] args) {System.out.println(Integer.valueOf(323)==Integer.valueOf(323));System.out.println(Integer.valueOf(23)==Integer.valueOf(23));}}代码四：public class MyTest1 {private static int a;public MyTest1(){System.out.println("a="+(++a));}public void test(){int a=5;System.out.println("a="+a);}public void test2(){a=5;System.out.println("a="+a);}public static void main(String[] args) {new MyTest1();new MyTest1();new MyTest1().test();System.out.println(a);new MyTest1().test2();System.out.println(a);}}代码五：public class Parent {public Parent(String name){System.out.println(name);}}public class Children extends Parent{public Children(String name){System.out.println(name);}public static void main(String[] args) {new Children("hello");}}