java 53個關鍵字和保留字

abstract class  extends implements null   strictfp   true
assert  const  false  import   package  super    try
boolean continue final  instanceof private  switch    void
break  default finally int    protected synchronized volatile
byte   do    float  interface public  this     while
case   double  for   long    return  throw
catch  else   goto  native   short   throws
char   enum   if   new    static  transient
 

八大基本資料型別

public class Demo01 {
  public static void main(String[] args) {
    //八大基本資料型別
    //整數
    int num1 = 10; //最常用
    byte num2 = 20;
    short num3 = 30;
    long num4 = 30L; //long型別要在數字後面加個L
​
    //小數:浮點數
    float num5 = 50.1F; //float型別要在數字後面加個F
    double num6 = 3.141592653589793238462643;
​
    //字元型別
    char name = 'A';
    //字串 String不是關鍵字，是一個類
    String name1 = "大小";
​
    //布林值:是非
    boolean flag = true;
    boolean flag1 = false;
​
   }
}