Draft: Test branch1

Summary by Bito

• New Java file 'test.java' added with user management functionality
• Multiple naming convention violations: class 'user_manager' and method 'Process_User_Data' use snake_case instead of camelCase
• Critical bug: line 25 uses assignment operator '=' instead of comparison '==' in null check (UserName=null)
• Variable naming inconsistency: field 'userName' declared but referenced as 'UserName' and 'AGE' throughout code
• Unsafe thread creation with direct Runnable instantiation and static field mutation in thread context
• Test method '@test' mixed with production code in same class violates separation of concerns
• Incomplete test logic: testPositive() expects 10 but someMethod() only returns input value (5)
• Missing newline at end of file