Java-through-C Compilation: An Enabling Technology for Java in Embedded Systems

Abstract

The Java programming language is acheiving greater acceptance in high-end embedded systems such as cellphones and PDAs. However, current embedded implementations of Java impose tight constraints on functionality, while requiring significant storage space. In addition, they require that a JVM be ported to each such platform.We demonstrate the first Java-to-C compilation strategy that is suitable for a wide range of embedded systems, thereby enabling broad use of Java on embedded platforms. This strategy removes many of the constraints on functionality and reduces code size without sacrificing performance. The compilation framework described is easily retargetable, and is also applicable to barebones embedded systems with no operating system or JVM.On an average, we found the size of the generated executables to be over 25 times smaller than those generated by a cuttingedge Java-to-native-code compiler, while providing performance comparable to the best of various Java implementation strategies.

Blueshell

“…A number of strategies for executing Java without a JVM on embedded processors have been demonstrated [15,14,12]. The work in this paper builds on the Chi [12] ahead-of-time Java compiler for processors with restricted resources.…”

Dexpler

“…Multiple tools based on Soot have been developed to perform transformations such as translation of Java to C [21], instrumentation of Java programs [23], obfuscator for Java [18], software watermarking [3], ... 2 .…”

Design and Optimization of a Java Ahead-of-Time Compiler for Embedded Systems

“…Platform independence is achieved by installing the Java virtual machine (JVM) on each platform [1], which executes Java's compiled executable called bytecode via interpretation. Since this software-based execution is much slower than hardware-based execution, compilation techniques that translate the bytecode into machine code have been employed, such as just-in-time compilation (JITC) [2,3] or ahead-of-time compilation (AOTC) [4][5][6][7][8]. JITC and AOTC perform the translation during runtime and before runtime, respectively.…”

“…There are two ways to server-AOTC. One is translating the bytecode directly into the machine code (bytecode-to-native) [8], and the other is translating the bytecode into the C code first, which is then compiled into the machine code [4][5][6][7] by an existing compiler such as gcc [15]. This bytecode-to-C (b-to-C) approach is more practical since it allows faster time-tomarket by using full optimizations of an existing compiler and by using its debugging and profiling tools.…”

“…Moreover, it allows a portable AOTC that can be used for multiple platforms without porting. In fact, many recent server-AOTCs took this approach [4][5][6][7][8].…”