There are different kinds of references in Java like strong, soft, weak, phantom etc. When you create a normal object using the new keyword and then assign it to a regular type, you are creating a strong reference. Garbage collector will only collect an object if there are no strong references to that object. Less strong references include soft, weak and phantom, and they are defined in the java.lang.ref package.

String interning is a method of storing only one copy of each distinct string value. Strings in Java are immutable and hence this sharing is perfectly safe and give you better performance. The distinct values are stored in a fixed-size hashtable usually referred to as string intern pool or string pool. The single copy of each string is called its 'intern'. You can read more about the basics of String interning with examples @ string-interning-in-java-with-examples.

Compilation occuring during program execution is called Just-In-Time compilation. There are 3 versions of the JIT compiler, and they are a 32-bit client version (-client), a 32-bit server version (-server) and a 64-bit server version (-d64). Oracle’s standard JVM implementation (that we download from oracle downloads page) is known as Hotspot JVM. 

Deadlock involves a mutual interdependence between two or more threads. 

First we will create an array (nested table array or varray), use it in a stored procedure and IN and/or OUT parameters and then populate and retrieve data through a JDBC program.

We can create a nested table array as:

CREATE TYPE array_table AS TABLE OF VARCHAR2 (50);

Or