Tech Trek: A Software Engineer's Guide to Code and Beyond

Advantages for declaring loggers as static Disadvantages for declaring loggers as static common and well-established idiom less CPU overhead: loggers are retrieved and assigned only once, at hosting class initialization less memory overhead: logger declaration will consume one reference per class For libraries shared between applications, not possible to take advantage of repository selectors. It should be noted that if the SLF4J binding and the underlying API ships with each application (not shared between applications), then each application will still have its own logging environment. not IOC-friendly Advantages for declaring loggers as instance variables Disadvantages for d...

 du -sm <dir_name>

1.  Liquibase is an open source database-independent library for tracking, managing and applying database changes. 2. All changes to the database are stored in XML files and identified by a combination of an "id" and "author" tag as well as the name of the file itself. 3. A list of all applied changes is stored in each database which is consulted on all database updates to determine what new changes need to be applied. 4. Liquibase executes changes based on this XML file to handle different revisions of database structures and data. 5. When you first run a changelog, LiquiBase manages those changelogs by adding two tables into your database. databasechangelog : maintains the database changes that were run. databasechangeloglock : ensures that two machines don't attempt to modify the database at one time. 6. Limitations do exist such that it will not export triggers, stored procedures, functions and packages. Sample changeLog file:  The above is...