java - Comparing Same Object of String with '==' and getting different result in both scenerio, where the String Object Value is same -

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in program 1 have declared 2 string , initialized them "madam". when running checking equality of reference variable (by '==' operator') getting "true" response.

but in program 2 declaring string 's' , initialize "madam". after running reverse loop , storing characters of 's' in reverse order in other string variable. have again tried check equality of reference variable (by '==' operator') , getting response 'false'. both string objects of same value , stored in constant pool area both variable should equate , output in both scenario should 'true'. why not same?

program 1:

class reverse {      public static void main(string[] args) {         string s="madam"; string rev="madam"; system.out.println(s==rev);     } } 

output - true

program 2:

class reverse {      public static void main(string[] args) {         string s="madam"; string rev="";          for(int x=s.length()-1;x>=0;x--) { rev+=s.charat(x); }             system.out.println(s==rev);     } } 

output- false

in program 1 java compiler saves "madam" string in 1 memory location , assigns both "s" , "rev" location hence "s==rev" returns true because both refer same address. should use "equals()" method compare 2 strings. e.equals(rev);

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