1-1程序代码：
package jxlPacakge;
public class ObjectEquals {
public static void main(String[] args) {
MyTestClass obj1=new MyTestClass(100);
MyTestClass obj2=new MyTestClass(100);
System.out.println(obj1==obj2);
System.out.println(obj1.equals(obj2));
}
}
class MyTestClass
{
public int Value;
//注意：只有参数类型为Object的，才是重写了Object的equals方法
//参数类型为MyTestClass的，仅仅是Overload了equals方法。
// @Override
// public boolean equals(Object obj)
// {
// return ((MyTestClass)obj).Value==this.Value;
// }
public boolean equals(MyTestClass obj)
{
return obj.Value==this.Value;
}
public MyTestClass(int initValue)
{
Value=initValue;
}
}
1-2程序截图：
2-1 程序代码
package jxlPacakge;
public class StrangeIntegerBehavior
{
public static void main(String[] args)
{
Integer i1=100;
Integer j1=100;
System.out.println(i1==j1);
Integer i2=129;
Integer j2=129;
System.out.println(i2==j2);
}
}
2-2 程序截图：
3-1程序代码
package jxlPacakge;
public class Test1
{
public static void main(String args[])
{
String str="abcd";
StringBuffer buff=new StringBuffer();
for(int i=str.length()-1;i>=0;i--)
buff.append(str.charAt(i));
System.out.println(buff.toString());
}
}
3-3 程序截图
4-1 程序代码
package jxlPacakge;
public class Test2
{
public static String reverseString(String inputStr)
{
StringBuffer buff=new StringBuffer();
for(int i=inputStr.length()-1;i>=0;i--)
buff.append(inputStr.charAt(i));
return buff.toString();
}
public static void main(String args[])
{
String str="abcd";
System.out.println(reverseString(str));
}
}
4-2 程序截图
5-1 程序代码
package jxlPacakge;
public class Test3
{
public static void main(String args[])
{
String str="abcd";
System.out.println(MyPackageClass.reverseString(str));
}
}
5-2 程序截图
6-1 程序代码：
package jxlPacakge;
class Root
{
static{
System.out.println("Root的静态初始化块");
}
{
System.out.println("Root的普通初始化块");
}
public Root()
{
System.out.println("Root的无参数的构造器");
}
}
class Mid extends Root
{
static{
System.out.println("Mid的静态初始化块");
}
{
System.out.println("Mid的普通初始化块");
}
public Mid()
{
System.out.println("Mid的无参数的构造器");
}
public Mid(String msg)
{
//通过this调用同一类中重载的构造器
this();
System.out.println("Mid的带参数构造器，其参数值：" + msg);
}
}
class Leaf extends Mid
{
static{
System.out.println("Leaf的静态初始化块");
}
{
System.out.println("Leaf的普通初始化块");
}
public Leaf()
{
//通过super调用父类中有一个字符串参数的构造器
super("Java初始化顺序演示");
System.out.println("执行Leaf的构造器");
}
}
public class TestStaticInitializeBlock
{
public static void main(String[] args)
{
new Leaf();
}
}
6-2程序截图
