Quick Refactoring of Parser.java - srini156

[srini156]

Changes

• file is made final & immutable via constructor.
• Removed duplicate code between getContent() and getContentWithoutUnicode(), using lambda function to filter.
• Using StringBuilder to construct file content.
• saveContent method made synchronized for thread safety.

Further enhancements:

• Use BufferedReader to read characters with charset.
• Use BufferedWriter to write string contents to the file.
• Take care of appropriate charset in saveContent.