The Java programming language and Java software platform have been criticized for design choices in the language and platform, including the implementation of generics, forced object-oriented programming, the handling of unsigned numbers, the implementation of floating-point arithmetic, and a history of security vulnerabilities in the primary Java VM implementation, HotSpot. Additionally, software written in Java, especially its early versions, has been criticized for its performance compared to software written in other programming languages. Developers have also remarked that differences in various Java implementations must be taken into account when writing complex Java programs that must be used across these implementations.