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Core Java - Interview Questions and Answers for 'String immutable' - 3 question(s) found - Order By Newest | ||||
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Ans. String is widely used as parameter for many java classes, e.g. network connection, opening files, etc. Making it mutable might possess threats due to interception by the other code segment or hacker over internet. Once a String constant is created in Java , it stays in string constant pool until garbage collected and hence stays there much longer than what's needed. Any unauthorized access to string Pool pose a threat of exposing these values. | ||||
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![]() Integer x = 1; Integer y = 2; System.out.println(x == y); What if you change 1 to "1" and Integer to String? | ||||
![]() Integer int1 = 1; Integer int2 = 1; String str1 = new String("str"); String str2 = new String("str"); String str3 = "str"; String str4 = "str"; System.out.println(int1 == int2); System.out.println(str1 == str2); System.out.println(str3 == str4); | ||||
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Ans. Because it doesn't make the change in the existing string but would create a new string by concatenating the new string to previous string. So Original string won't get changed but a new string will be created. That is why when we say str1.concat("Hello"); It means nothing because we haven't specified the reference to the new string and we have no way to access the new concatenated string. Accessing str1 with the above code will still give the original string. | ||||
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Ans. Because String being an immutable object creates a new object upon each concatenation cycle. If there is any such need , we should use String Builder whose objects are mutable. | ||||
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