Difference between matches and equalsIgnoreCase or equals in string class

Question

matches: Will check if the complete string entered is equal to the value present in the string object.

equalsIgnoreCase: Ignoring the case, it checks if the string entered is equal to the value present in the string object.

equals: Case sensitive and it checks if the string entered is equal to the value present in the string object.

This is what I know about the methods, present in String class.

Are there any other differences(Am I missing any valuable differences)?

If there are no differences, then why cant matches method be removed from String class, since the functionality it puts forth can be achieved using the other above mentioned methods, appropriately.

Answer 1

There is a big difference - matches checks the match of a String to a regular expression pattern, not the same string. Do not be mislead by the fact that it receives a String as an argument.

For example:

"hello".equals(".*e.*"); // false
"hello".matches(".*e.*"); // true

Answer 2

The key difference is that matches matches a regular expressions whereas equals matches a specific String.

System.out.println("hello".matches(".+"));    // Output: true
System.out.println("hello".equals(".+"));     // Output: false
System.out.println("wtf?".matches("wtf?"));   // Output: false
System.out.println("wtf?".equals("wtf?"));    // Output: true

I suggest you have a look at what a regular expression is