Krakatau is a Java bytecode analysis toolkit that provides assembler and disassembler capabilities for Java classfiles. The tool converts binary Java classfiles into human-readable text format, enabling analysts to examine the low-level structure and implementation details of Java applications. It supports the creation of new classfiles from scratch by allowing users to write bytecode manually in text format. Krakatau includes decompilation functionality that converts Java binaries back to readable source code, making it useful for reverse engineering Java applications. The tool can handle highly obfuscated code and supports some undocumented JVM features found in older versions. The disassembler output allows for detailed examination and comparison of Java binaries at the bytecode level. This capability is particularly valuable for malware analysis, security research, and understanding the inner workings of Java applications. The tool has limitations with newer Java features, specifically lacking support for Java 8+ constructs such as lambda expressions. It focuses primarily on traditional Java bytecode structures and older JVM implementations.