Proper use of close () and = null for Closable objects

Question

Let's say I'm using a database connection with a name con(or a socket or something else that is Closable). What happens after close()? Does the convalue increase nullor is it something else? And what is the difference between con.close()and con = null?

Answer 1

When you call close, the object should free all the resources that it uses behind the scenes. In the case of an instance, java.sql.Connectionthis will be one of two things:

• Release any physical database connection by freeing up resources. This happens when you open a database connection manually, for example. DriverManager.getConnection(...).
• SLEEPING , . , Connection DataSource, .

con = null null , , . Connection null close, .

close Closeable try-with-resources ( Java 7), , ) .