Oracle Exam 1Z0-829 Topic 10 Question 18 Discussion

The code fragment compares four pairs of strings using the equals() and intern() methods. The equals() method compares the content of two strings, while the intern() method returns a canonical representation of a string, which means that it returns a reference to an existing string with the same content in the string pool. The string pool is a memory area where strings are stored and reused to save space and improve performance. The results of the comparisons are as follows:

s1.equals(s2): This returns true because both s1 and s2 have the same content, ''Hello Java 17''.

s1 == s2: This returns false because s1 and s2 are different objects with different references, even though they have the same content. The == operator compares the references of two objects, not their content.

s1.intern() == s2.intern(): This returns true because both s1.intern() and s2.intern() return a reference to the same string object in the string pool, which has the content ''Hello Java 17''. The intern() method ensures that there is only one copy of each distinct string value in the string pool.

''Hello Java 17'' == s2: This returns false because ''Hello Java 17'' is a string literal, which is automatically interned and stored in the string pool, while s2 is a string object created with the new operator, which is not interned by default and stored in the heap. Therefore, they have different references and are not equal using the == operator.