Learn Java-8 from scratch. Create the first object and the first object in java-8

Learn Java-8 from scratch. Create the first object and the first object in java-8

1. Create an object;
2. Use attributes to describe objects;
3. Determine the behavior of the object;
4. merge objects;
5. inherit from other objects;
6. Convert the object and other types of information.

 

Program NewRoot2: calculates the square root of the input number and outputs

 1 package com.jsample; 2  3 public class NewRoot2 { 4     public static void main(String[] args){ 5         int number = 100; 6         if (args.length > 0){ 7             number = Integer.parseInt(args[0]); 8         } 9         System.out.println("The square root of "10                 + number11                 + " is "12                 + Math.sqrt(number)13         );14     }

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Output:

The square root of 169 is 13.0

 

Program ModemTester: test the functions of the following four classes

 1 package com.jsample; 2  3 public class ModemTester { 4     public static void main(String[] args){ 5         CableModem surfBoard = new CableModem(); 6         DslModem gateway = new DslModem(); 7         AcousticModem acoustic = new AcousticModem(); 8         surfBoard.speed = 500000; 9         gateway.speed = 400000;10         acoustic.speed = 300;11         System.out.println("Trying the cable modem:");12         surfBoard.displaySpeed();13         surfBoard.connect();14         System.out.println("Trying the DSL modem");15         gateway.displaySpeed();16         gateway.connect();17         System.out.println("Trying the acoustic modem");18         acoustic.displaySpeed();19         acoustic.connect();20         System.out.println("Closing all modems");21         surfBoard.disconnect();22         gateway.disconnect();23         acoustic.disconnect();24     }25 }

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Subordinate class: Modem

 1 package com.jsample; 2  3 public class Modem { 4     int speed; 5  6     public void displaySpeed(){ 7         System.out.println("Speed: " + speed); 8     } 9 10     public void disconnect(){11         System.out.println("Disconnecting to the Internet");12     }13 }

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Subordinate class: CableModem

 1 package com.jsample; 2  3 public class CableModem extends Modem{ 4     String method = "cable connecttion"; 5  6     public void connect(){ 7         System.out.println("Connecting to the Internet"); 8         System.out.println("Using a " + method); 9     }10 }

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Subordinate class: DslModem

 1 package com.jsample; 2  3 public class DslModem extends Modem{ 4     String method = "DSL phone connection"; 5  6     public void connect(){ 7         System.out.println("Connecting to the Internet"); 8         System.out.println("Using a " + method); 9     }10 }

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Subordinate class: AcousticModem

 1 package com.jsample; 2  3 public class AcousticModem extends Modem{ 4     String method = "acoustic connection"; 5  6     public void connect(){ 7         System.out.println("Connecting to the Internet"); 8         System.out.println("Using a " + method); 9     }10 }

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Output:
Trying the cable modem:
Speed: 500000
Connecting to the Internet
Using a cable connecttion
Trying the DSL modem
Speed: 400000
Connecting to the Internet
Using a DSL phone connection
Trying the acoustic modem
Speed: 300
Connecting to the Internet
Using a acoustic connection
Closing all modems
Disconnecting to the Internet
Disconnecting to the Internet
Disconnecting to the Internet