Java is a high level language.( Challenge )

Question

so why only "System " class in java
interact with the hardware

Answer 1

Embedded systems use specialized I/O devices to interact with their environment, and since they have to be de-pendable, it is attractive to use a modern, type-safe programming language like Java to develop programs for them. However, standard Java, as a platform independent language, delegates access to I/O devices, direct mem-ory access and interrupt handling to some underlying operating system or kernel, but in the embedded systems domain resources are scarce and a Java virtual machine (JVM) without an underlying middleware is an attractive architecture. The contribution of this paper is a proposal for Java packages with hardware objects and interrupt handlers that interfaces to such a JVM. We provide implementations of the proposal directly in hardware, directly as extensions of standard interpreters, and finally with an operating system middleware. The latter solution is mainly seen as a migration path allowing Java programs to coexist with legacy system components. An important aspect of the proposal is that it is compatible with the Real-Time Specification for Java (RTSJ).