Trivia

Question

Explain:
class test
     public static void main(String args[])
          String file = "-134343";
          System.out.println(file.substring(0,2));
          if(file.substring(0,2) == "-1")
          System.out.println("yes");
          String file1 = "-1";
          System.out.println(file1.substring(0,2));
          if(file1.substring(0,2) == "-1")
          System.out.println("yes");
o/p is:
-1
-1
yes
why not yes in both cases??

Answer 1

Why not review the source code for method substring? Realize that other implementations of substring can yield different results.
public String substring(int beginIndex, int endIndex) {
     if (beginIndex < 0) {
         throw new StringIndexOutOfBoundsException(beginIndex);
     if (endIndex > count) {
         throw new StringIndexOutOfBoundsException(endIndex);
     if (beginIndex > endIndex) {
         throw new StringIndexOutOfBoundsException(endIndex - beginIndex);
     return ((beginIndex == 0) && (endIndex == count)) ? this :
         new String(offset + beginIndex, endIndex - beginIndex, value);
    }Note "this".
Message was edited by:
DrLaszloJamf