Although many different model transformation languages (MTLs) and model transformation frameworks (MTFs) exist, each of them is requiring a developer to learn an additional language. Moreover since many of them follow a declarative approach, they are often less intuitive programmers familiar with imperative language. Therefore a java based imperative library called jTL has been developed which enables the user to write the whole transformation process in pure Java. The resulting jTL should be applicable to a wide range of transformation tasks that include classical graph based source models or especially source code translation, because transformation of legacy code is still a not yet solve challenge in software migration. Since source code transformation is a quite complex and performance intensive task, the jTL represents an easy to use approach, which focuses on goals like maintainability, readability, reusability and performance improvements. To achieve these goals two similar existing approaches were examined to uncover weaknesses and deduce possible improvements for the resulting jTL. Moreover jTL should further benefit from adding new Java 8 features like bulk operation, lambda expression, functional interface and parallel stream processing. Although the jTL has been kept as simple as possible, it is still a complete transformation approach, since it also supports further important features like tracing or reuse mechanisms like rule inheritance which should be part of every state of the art transformation language. As an evaluation, two concrete transformation examples are given that make use of jTL. This should give an idea how a transformation with jTL can be established and what differences and improvements come up with jTL in contrast to other Java based transformation solutions.