In this article, we present a reusable Java processor IP for application processors of embedded systems. For the Java microarchitecture, we propose a low-cost stack memory design that supports a two-fold instruction folding pipeline and a low-complexity Java exception handling hardware. We also propose a mapping between the Java dynamic class loading model and the SoC platform-based design principle so that the Java core can be encapsulated as a reusable IP. To achieve this goal, a two-level method area with two on-chip circular buffers is proposed as an interface between the RISC core and the Java core. The proposed architecture is implemented on a Xilinx Virtex-5 FPGA device. Experimental results show that its performance has some advantages over other Java processors and a Java VM with JIT acceleration on a PowerPC platform.