Is it necessary to install Java SDK to run Java programs?

To run Java programs on a computer, Java Runtime Environment (JRE) is required, which contains the Java Virtual Machine (JVM). However, to compile Java source code into bytecode, the Java Development Kit (JDK) is necessary, which includes the javac compiler and other tools.

If you already have a compiled .class file or .jar, then JRE is sufficient for running. But if you want to write and compile Java code, installing the JDK is mandatory.

In the context of Android development, Android Studio is usually used, which includes its own set of tools and SDK, but for building Java projects, the JDK is also needed.