[Example implementation](https://github.com/exercism/java/blob/master/exercises/rna-transcription/.meta/src/reference/java/RnaTranscription.java)

- Class: define a class to resolve the problem

- Methods: define a method to contain the logic

- Argument: the method should take the input as argument

- Strings: input and output of the class method are strings

- Assignment: assign some objects to local variables

- Variables: define references to created objects

- Loops: iterate on every character of the input string

- Objects: create a object of class `StringBuilder` to store the transcription

- Return values: method should return the final transcription

- Pattern matching: match the right operation to execute depending on the input value

- Error handling: manage the scenario when an invalid value is found

- use conditional instead of pattern matching to choose the right operation to execute for the input value

- use stream instead of loops to iterate on input values and map operation with a method reference to transform the data