Introduction: Why Compare PL/SQL and Java in Oracle?

Oracle introduced Java stored procedures in Oracle 8i, allowing Java to be used inside the database. But if Java is so powerful, why is PL/SQL still widely used?

This guide explains the differences between PL/SQL and Java in the Oracle database environment, with examples and a simple layout for easy learning.

PL/SQL vs Java – Key Differences

Feature / Criteria	PL/SQL	Java in Oracle
Integration with Oracle	Native, tightly integrated	Supported via Java stored procedures
Compilation	Can be compiled to native C (faster)	Compiled into Java bytecode
Syntax Simplicity	Simple and SQL-friendly	More verbose and complex
Object-Oriented Features	Limited but improving (Oracle 10g+)	Fully OOP
Execution Mode	Procedural blocks run directly	Needs Java Virtual Machine (JVM)
Use Case	Ideal for SQL-heavy business logic	Great for complex logic, file I/O, etc.
Performance	Faster for DB-related tasks	Slower for simple DB interactions
Ease of Learning	Easier for DBAs and SQL users	Requires Java knowledge

Why Use PL/SQL Instead of Java?

PL/SQL is specially designed for Oracle databases. It offers several advantages:

Tight Integration
PL/SQL works seamlessly with SQL and Oracle features like triggers, cursors, exceptions, and stored procedures.
Faster Performance with Native Compilation
Oracle allows PL/SQL to be natively compiled to C code, improving performance by up to 30% over interpreted mode.
Simplicity
You can turn any SQL into a PL/SQL block with just:

BEGIN
  NULL;
END;
/

4. Consistency with SQL

PL/SQL now shares the same parser as SQL. This means your SQL queries behave the same inside or outside PL/SQL.

5. Growing Object-Oriented Features

Oracle continues to add object-oriented features to PL/SQL, like object types and method support.

When to Use Java in Oracle?

Java is not a replacement for PL/SQL but a powerful alternative when you need features like:

Network access (sockets, HTTP)
File I/O operations
Multithreading
Advanced math libraries

Example of a Java stored procedure in Oracle:

import java.sql.*;
public class HelloWorld {
  public static void hello() {
    System.out.println("Hello from Java inside Oracle!");
  }
}

Then, load and call it from SQL:

CREATE OR REPLACE JAVA SOURCE NAMED "HelloWorld" AS
  <insert java code above here>;

CALL dbms_java.loadjava('HelloWorld');