What are the main functions of an Assembler?

Java

An assembler is used to convert low-level assembly language into machine code. Assembly language is a symbolic language that maps 1:1 with the machine code produced by the assembler.

A compiler is used to convert a high-level language into a low-level language such as intermediate byte code, assembly or native machine code.

An interpreter is used to convert a high-level language or byte code into native machine code. Statements are typically converted to machine code instructions one statement at a time, rather than all at once.

All high-level are either compiled or interpreted, however some are both compiled and interpreted. Most compiled languages compile to machine code, however some, such as Java, compile to an intermediate byte code which must then be interpreted to produce the machine code.