How do I find a particular substring in a string in Java?

You can use contains(), indexOf() and lastIndexOf() method to check if one String contains another String in Java or not. If a String contains another String then it’s known as a substring. The indexOf() method accepts a String and returns the starting position of the string if it exists, otherwise, it will return -1.

REGEXP_SUBSTR extends the functionality of the SUBSTR function by letting you search a string for a regular expression pattern . It is also similar to REGEXP_INSTR , but instead of returning the position of the substring, it returns the substring itself.

The reason is, that first the Java compiler interprets the two \\ characters as an escaped Java String character . After the Java compiler is done, only one \ is left, as \\ means the character \ . The string thus looks like this: \.5 Mar 2019