I understand that String objects are immutable, so these when you apply these methods to a String object, a new String object is returned. Above, both the substring() and trim() should return "String". So, why do they give different results when compared to "String"?
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Since Strings are immutable....performing trim() on " String " would not affect the original string(i.e. " String "). Therefore you are comparing " String " with "String"...which is obviously FALSE.
No. " String ".trim() is equal to "String", so the two strings have the same value. But the trim operation creation a new String object, and since "==" test for object equality -not string equality- the result is false. [ May 13, 2008: Message edited by: Ulf Dittmer ]
* 'new' operator ALWAYS creates an object on heap. * All methods in String class which return a string (toUpperCase(), toLowerCase(), trim() etc.) create the new object on heap, ONLY if required. If not required (say there are no white-spaces to trim), the same instance is returned.