Java ME

About

Java ME (Java Platform, Micro Edition) is a subset of the Java platform tailored for embedded systems and resource-constrained devices such as feature phones, set-top boxes, industrial controllers, and IoT devices.

• Target: Small devices with limited memory, display, and power (e.g., 128 KB–1 MB RAM)

• Origin: Initially called J2ME (Java 2 Micro Edition)

• Current: Part of the overall Java Platform but less prominent due to rise of smartphones and IoT-specific platforms

• Base: Subset of Java SE APIs with additional libraries for device-specific capabilities

Components

Configurations

Define the basic runtime environment:

• CLDC (Connected Limited Device Configuration): For devices with very limited resources

• CDC (Connected Device Configuration): For more capable devices (e.g., set-top boxes)

Profiles

Built on top of configurations to add more APIs:

• MIDP (Mobile Information Device Profile): For mobile phones and PDAs

• Foundation Profile: For CDC-based devices

Optional Packages

• Bluetooth (JSR 82)

• Wireless Messaging API (JSR 205)

• Mobile Media API (JSR 135)

• Location API (JSR 179)

Development Tools

• Java ME SDK: Provided by Oracle

• Eclipse ME: Plugin for Eclipse

• NetBeans: Better out-of-box support for Java ME

• Emulators: Used to test applications on different device profiles

Deployment Model

• .jar/.jad files: Java Application Descriptor (JAD) used alongside the JAR for deployment to mobile phones

• OTA (Over-the-Air) provisioning

Java ME vs Java SE

Feature	Java ME	Java SE
Target Devices	Mobile, embedded, IoT	Desktop, server
API Coverage	Subset + mobile extensions	Full standard APIs
GUI Support	Limited (LCDUI in MIDP)	Swing, JavaFX
Networking	Mobile-optimized	Full TCP/IP, RMI
Security	Sandbox, permissions	Full JVM security

Real-World Use Cases

• Feature phones (e.g., Nokia Series 40, Motorola)

• Payment terminals

• RFID scanners

• Set-top boxes

• Industrial automation

• Early GPS/Location-based apps

Decline and Transition

• Smartphones (Android, iOS) replaced the need for Java ME in consumer mobile devices

• Android uses a separate Java-based runtime (Dalvik/ART) not based on Java ME

• Java ME Embedded and Java ME 8 attempted to modernize the platform for IoT

• IoT is now largely handled by other languages/frameworks: C, Python, Node.js, etc.

Future and Current Status

• Java ME is not actively evolving

• Used in legacy systems and niche embedded devices

• Oracle focuses on Java SE for embedded solutions now

• Eclipse IoT and Jakarta EE are modern replacements in enterprise and IoT space