Why does Java's String#replace() method work differently with characters and strings?

Question

Why does the following expression evaluate as false

aStr.replace("H", "H") == "Hello"

while this alternate expression evaluates as true?

aStr.replace('H', 'H') == "Hello"

Answer 1

Java caches String literal in String pool, so if there is no change in String it would take an immutable instance from pool and so that both refers to same instance in memory and thus == on reference returns true

So to compare String Object you should use equals() method / compareTo() method

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Also See

• What is String pool in Java?
• Java String.equals versus ==