Bytecode Explained

Bytecode Explained

What is bytecode?

Bytecode offers the possibility of guaranteeing the performance of a program across platforms. This serves as “intermediate code”, which interprets the commands of the source code and translates them into the required target language for the respective hardware.

A bytecode is part of a programming language , for example Java or Python . It comprises a collection of instructions that are used to compile the code into the required machine code.

The bytecode thus triggers the creation of an intermediate code, i.e. a quasi-translator from programming code to machine code. The route via the automatically generated intermediate code has various advantages in cross-platform programming .

Advantages and disadvantages of bytecode

A major challenge when using interpreters is that they allow conclusions to be drawn about the source code . The source code is not “read out”, but it can be interpreted and rebuilt with a similar functionality. This entails great dangers relating to data security and also to copyright.

A reproduced source code may look different from the original in terms of syntax, but it can provide a similar range of functions. With the bytecode, an effective tool has been developed which inhibits this development. The technical term for this is “obfuscation” and means something like “concealment”.

In summary, the following advantages result from using a bytecode:

  • Obfuscation despite applicability for different machine codes.
  • Easy interpretation of a syntax.
  • The front-end part of a language can be ignored by using bytecode.
  • Can be used as an analysis tool to find programming errors.
  • The syntax of the surface can be changed and is reinterpreted on the fly by the bytecode.

However, there are also disadvantages with the use of bytecode. These are:

  • Great effort on the bytecode interface
  • High effort when comparing versions
  • Increased complexity of semantics

Use of the bytecode

The idea of ​​bytecode was developed when the variety of hardware and software manufacturers continued to increase. In the days of IBM calculating machines and FORTRAN, the use of a bytecode was not yet necessary. With the emergence of PASCAL and the increasing spread of hardware, one was forced to develop a solution that would enable PASCAL programs to run on as many computers as possible.

In today’s predominantly cloud-based, networked IT, the problem of hardware diversity is considerably increased. Java with its “virtual machine” approach is therefore ideal for implementing and executing a bytecode that can be interpreted and used by as many platforms as possible.

Programming languages ​​that use bytecode

In addition to Python and Java, the following programming languages ​​also use the bytecode function in order to remain as broadly applicable as possible:

  • Lua
  • All .NET languages ​​like C #, F #, Visual Basic
  • Ruby
  • Pearl
  • PHP
  • prolog
  • limbo
  • Gambass
  • Tcl

The use of the bytecode, however, differs within the individual languages. Java, Python and .Net use the bytecode as a “compilation” and execute it independently of the source code. With the script languages Perl (up to V5) and TCL, the source code is compiled from the byte code when the program is started and only stored in the main memory as long as the program is active.

Influence of the bytecode on computing times

Every increase in the complexity of a syntax has consequences for the computing time. However, the bytecode as used for Java Virtual Machines only increases the start time of the program. As soon as the program is running, there is no longer any delay caused by the bytecode. For this purpose, special just-in-time compilers are integrated, which permanently interpret the byte code while the program is running.

Bytecode Explained