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