To Java

The current regular expression is transformed to be used in a Java program. The result is given in its literal form (example: (?im)\\b(\\w+)\\b \\b\\1\\b) and in its compiled form (example: Pattern.compile("\\b(\\w+)\\b \\b\\1\\b", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE);).
The flags are automatically encoded.

From Java

An Java-coded regular expression can be copy-pasted in this field. Expressions like the ones produced in the To Java field are accepted and the flags are automatically updated.