equals() method of the String class in Java https://coderolls.com/compare-strings-in-java/

equals

public boolean equals(Object anObject)

It compare this string with the argument strings and return true if the argument is not null and contains the same character as the specified string.

param -
another string

returns -

true - if argument is not null and it contains same characters as the specified string
false - if the argument is null or it does not contain same characters as the specified string

ex. firstString.equals(secondString)
// returns true if and only if the secondString is not null and contains the same characters as firstString.