how to compare sb and s
StringBuffer sb= new StringBuffer("Hello");
String s= "Hello";
s.equals(sb.toString()) is giving result as false.
5 Answers
Unable to reproduce:
public class Test {
public static void main(String[] args) {
StringBuffer sb= new StringBuffer("Hello");
String s= "Hello";
System.out.println(s.equals(sb.toString())); // Prints true
}
}
If you think the two values are really the same, please post a similar short but complete program demonstrating the problem. I suspect you'll find the problem is elsewhere - such as some invisible characters in the string or StringBuffer.
Comments
It is definitely returning true for me. As the content of both strings (the String object you created and the String object returned by the StringBuffer toString()) are the same, the equals() method shouldn't return false.
Comments
It will give false, when you will able to compare without using toString() on StringBuffer Object.
Like:
StringBuffer s=new StringBuffer("abc");
String s1="abc";
System.out.println(" "+s1.equals(s));
Comments
use s.contentEquals(sb);
This will work .
4 Comments
mjp66
This does not provide an answer to the question. To critique or request clarification from an author, leave a comment below their post - you can always comment on your own posts, and once you have sufficient reputation you will be able to comment on any post. - From Review
Tom
@mjp66 This does not provide an answer ... because? Since you seem to be new to this review queue please read this: meta.stackexchange.com/questions/185073/…
mjp66
@Tom You're right, I flubbed here. I often post a quick one-line answer as a comment. I flagged it as NaA as it doesn't elaborate (my mistake, I thought these types of answers were frowned upon). Thanks!
Tom
@mjp66 You have to differ between "not an answer" (something like a new question, spam or "thanks") and bad answers (incomplete or broken code snippets; wouldn't solve the problem). The first one needs flags and the second one needs comments and/or downvotes. So in this case: a comment about the missing explanation (and maybe a downvote) would be correct to "handle" this. Btw: a lot of people handle answers incorrectly, so no worries, that happens. And this is also nice to read: meta.stackexchange.com/questions/225370/….
Equals and == will not work for comparision of StringBuffer and String.
== will work only for comparisions among the same non-collections [ integers, characters etc.]
equals method will work only for comparisons among the same collections [ array, string, objects etc.]
Note : Comparisions between different collections or non-collection leads to error.
class ClassName{
public static void main(String[] args) {
// STRING VS STRING BUFFER
String strg = "Hello";
StringBuffer strgBuf = new StringBuffer(strg);
//if(strg == strgBuf ) //=> error: incomparable types: String and StringBuffer
if(strg.equals(strgBuf))
System.out.println("strg.equals(strgBuf) is true");
else
System.out.println("strg.equals(strgBuf) is false") ;
//=> strg.equals(strgBuf) is false
// 2 STRINGS COMPARED
if(strg.equals(strgBuf.toString()))
System.out.println("strg.equals(strgBuf.toString()) is true");
else
System.out.println("strg.equals(strgBuf.toString()) is false");
//=> strg.equals(strgBuf.toString()) is true
// STRING BUFFER VS STRING BUFFER
StringBuffer strgBuf2 = new StringBuffer(strg);
if(strgBuf2 == strgBuf)
System.out.println("strgBuf2 == strgBuf is true");
else
System.out.println("strgBuf2 == strgBuf is false") ;
//=> strgBuf2 == strgBuf is false
if(strgBuf2.equals(strgBuf))
System.out.println("strgBuf2.equals(strgBuf) is true");
else
System.out.println("strgBuf2.equals(strgBuf) is false") ;
//=> strgBuf2.equals(strgBuf) is false
// 2 STRINGS COMPARED
if(strgBuf2.toString().equals(strgBuf.toString()))
System.out.println("strgBuf2.toString().equals(strgBuf.toString()) is true");
else
System.out.println("strgBuf2.toString().equals(strgBuf.toString()) is false") ;
//=> strgBuf2.toString().equals(strgBuf.toString()) is true
// STRING VS STRING
String strg2 = new String(strg);
if(strg == strg2)
System.out.println("strg == strg2 is true");
else
System.out.println("strg == strg2 is false") ;
//=> strg == strg2 is false
if(strg.equals(strg2))
System.out.println("strg.equals(strg2) is true");
else
System.out.println("strg.equals(strg2) is false") ;
//=> strg.equals(strg2) is true
}
}
equalsIgnoreCase(), if it goes true then there is something about the casing of one of the values.