Java中常见的陷阱题及答案

public static boolean isOdd(int i){
 return i % 2 == 1;
 }

System.out.println(2.0-1.9);

System.out.println(0.05+0.01);
System.out.println(1.0-0.42);
System.out.println(4.015*100);
System.out.println(123.3/100);

if(0.05+0.01-0.06 < 0.0000001)
{
}

System.out.println((new BigDecimal("2.0")).subtract(
 new BigDecimal("1.9")).doubleValue());

public static final int END = Integer.MAX_VALUE;
 public static final int START = END - 2;
 
 public static void main(String[] args) {
 int count = 0;
 for (int i = START; i <= END; i++)
 count++;
 System.out.println(count);
 }

public static boolean decision() {
 try {
 return true;
 } finally {
 return false;
 }
}

int a=5;
  System.out.println("value is"+((a<5)? 10.9:9 ));

value is9.0

StringBuffer str1=new StringBuffer("123");
  StringBuffer str2=new StringBuffer("123");
  if(str1.equals(str2)){
   System.out.println("str1.equalstr2");
  }else{
   System.out.println("str1.notequalstr2");
  }

Float fa=new Float(0.9f);
  Float fb=new Float(0.9f); //Float fb=new Float("0.9f");
  Double db=new Double(0.9f);
  if(fa==fb){ //false
   System.out.println("fa==fb");
  }else{
   System.out.println("fa!=fb");
  }
  if(fa.equals(fb)){ //true
   System.out.println("fa.equalfb");
  }else{
   System.out.println("fa!equalfb");
  }
  if(db.equals(fb)){ //false
   System.out.println("db.equalfb");
  }else{
   System.out.println("db!equalfb");
  }

fa!=fb
fa.equalfb
db!equalfb Float 型与Double 型肯定不相等