The brilliant idea of composing existing components to build software systemsinstead of developing new software systems from scratch was rst brought up byM.D. McIlroy in 1968. His idea was an \industrial revolution" of software pro-duction. When we look at the modern object-oriented programming languagesand their paradigms, we will see that the components never became a base el-ement of them and that they exist with the help of external mechanisms likeframeworks. Creating a brand new programming language which is built on theidea of component-based software development could solve the problem, but thisalso means throwing away all valuable work done until today with the existingobject-oriented languages. The central question of this thesis is how to make itpossible to program component-based while still bene ting from an object-orientedprogramming language.An embedded domain speci c language (DSL) gives us the opportunity to in-sert the component concept into the Java programming language by extending it.In that way, I include the component keywords in the DSL and still bene t fromthe Java language concepts like classes. I develop a DSL with the developmentenvironment called MPS - Meta Programming System which is being developedby JetBrains. I call the DSL I develop, Java Component Language (JCL) whichexpresses that it is a sum of the Java programming language and a componentlanguage (extended Java by component keywords). The resulting language JCL,is a developing tool which makes it possible to program with components in Java.