package net.mindview.initialization;
public class Test1 {
public String str;
public static void main(String[] args) {
Test1 t = new Test1();
System.out.println(t.str);
}
}
package net.mindview.initialization;
public class Test2 {
public String str1 = "abc";
public String str2;
public Test2(){
System.out.println(str1);
System.out.println(str2);
this.str2 = "def";
System.out.println(str1);
System.out.println(str2);
}
public static void main(String[] args) {
Test2 t = new Test2();
}
}
package net.mindview.initialization;
public class Test3 {
public Test3(){
System.out.println("默认构造器");
}
public static void main(String[] args) {
Test3 t = new Test3();
}
}
package net.mindview.initialization;
public class Test3 {
public Test3(){
System.out.println("默认构造器");
}
public Test3(String str){
System.out.println("有一个参数的构造器");
System.out.println(str);
}
public static void main(String[] args) {
Test3 t = new Test3();
Test3 t2 = new Test3("hello");
}
}
package net.mindview.initialization;
public class Dog {
public void bark(){
System.out.println("barking");
}
public void bark(String paoxiao){
System.out.println("howling");
}
public static void main(String[] args) {
Dog dog1 = new Dog();
dog1.bark();
dog1.bark("paoxiao");
}
}
package net.mindview.initialization;
public class Test8 {
public void method1(){
System.out.println("1");
method2().method2();
}
public Test8 method2(){
System.out.println("2");
return this;
}
public static void main(String[] args) {
Test8 t = new Test8();
t.method1();
}
}
package net.mindview.initialization;
public class Test10 {
@Override
protected void finalize() throws Throwable {
System.out.println("调用了finalize方法");
super.finalize();
}
public static void main(String[] args) {
Test10 t = new Test10();
t = null;
System.gc();
Test10 t1 = new Test10();
t1 = null;
System.gc();
}
}
package net.mindview.initialization;
public class Test10 {
@Override
protected void finalize() throws Throwable {
System.out.println("调用了finalize方法");
super.finalize();
}
public static void main(String[] args) {
Test10 t = new Test10();
t = null;
System.gc();
Test10 t1 = new Test10();
t1 = null;
System.gc();
System.runFinalization();
}
}
package net.mindview.initialization;
public class Tank {
public String state = "empty";
public Tank(String state){
this.state = state;
}
void clear(){
this.state = "empty";
}
@Override
protected void finalize() throws Throwable {
System.out.println("------finalize---------");
if(!state.equals("empty")){
System.out.println("Error!!Tank未被清空");
}
super.finalize();
}
public static void main(String[] args) {
Tank tank1 = new Tank("full");
tank1.clear();
System.gc();
System.runFinalization();
Tank tank2 = new Tank("full");
tank1 = null;
tank2 = null;
System.gc();
System.runFinalization();
}
}
package net.mindview.initialization;
public class Test14 {
public static String str1 = "abc";
public static String str2;
static {
str2 = "def";
}
public static void print(){
System.out.println("str1 :"+ str1);
System.out.println("str2 :"+ str2);
}
public static void main(String[] args) {
print();
}
}
package net.mindview.initialization;
public class Test14 {
public static String str1 = "abc";
public static String str2;
public String str3;
//静态成员初始化
static {
str2 = "def";
//str3 = "aaa"; //报错
}
//非静态成员初始化
{
str3 = "aaa";
str2 = "mmm";//也可以给静态成员初始化
}
public static void print(){
System.out.println("str1 :"+ str1);
System.out.println("str2 :"+ str2);
}
public static void main(String[] args) {
Test14 t = new Test14();
print();
System.out.println("str3 :"+ t.str3);
}
}
package net.mindview.initialization;
public class Test17 {
public Test17(String str){
System.out.println(str);
}
public static void main(String[] args) {
Test17[] tt = null;
}
}
package net.mindview.initialization;
import java.util.Random;
public class Test17 {
public Test17(String str){
System.out.println(str);
}
public static void main(String[] args) {
Random rand = new Random();
Test17[] tt = new Test17[rand.nextInt(100)];
for(int i=0;i<tt.length; i++){
tt[i] = new Test17(""+i);
}
}
}
package net.mindview.initialization;
public class Test19 {
public void print(String ...strings){
for(String str: strings){
System.out.print(str);
}
System.out.println();
}
public static void main(String[] args) {
Test19 t = new Test19();
t.print("aaa", "bbb", "ccc");
t.print(new String[]{"d","e","f"});
}
}
package net.mindview.initialization;
public class Test19 {
public static void main(String ...args){
for(String arg: args){
System.out.println(arg);
}
}
}
package net.mindview.initialization;
enum Money{
ONE,
TWO,
FIVE,
TEN,
FIVTY,
HUNDRED
}
public class Test21 {
public static void main(String[] args) {
for(Money m : Money.values()){
System.out.println(m + " " + m.ordinal());
}
}
}
package net.mindview.initialization;
enum Money{
ONE,
TWO,
FIVE,
TEN,
FIFTY,
HUNDRED
}
public class Test22 {
Money value;
public Test22(Money value){
this.value = value;
}
public void printValue(){
switch(value){
case ONE:
System.out.println("1元面值");
break;
case TWO:
System.out.println("2元面值");
break;
case FIVE:
System.out.println("5元面值");
break;
case TEN:
System.out.println("10元面值");
break;
case FIFTY:
System.out.println("50元面值");
break;
case HUNDRED:
System.out.println("100元面值");
break;
}
}
public static void main(String[] args) {
Test22 t = new Test22(Money.ONE);
Test22 t2 = new Test22(Money.TWO);
Test22 t3 = new Test22(Money.HUNDRED);
t.printValue();
t2.printValue();
t3.printValue();
}
}