How to use java reflection to implement methods

This task is about a basic decompiler and how could i fill in the following several methods marked as comment? thanks

getMethodInfo() returns a string object which contains the method header(visibility, modifiers, return type, name, parameter list)

getClassInfo() returns a string object representing the head of the class definition without the { opening for the body

getFieldInfo() returns a string object containing the definition of a given field without a potential initialization value.

getConstructorInfo() returns a string object containing the definition of a given constructor, including parameters.

    public String decompile(Class<?> clazz) {
        StringBuilder stringBuilder = new StringBuilder(getClassInfo(clazz))
                .append("{");

        /* iterate over all constructors and add them to the output string */  

     

        /* iterate over all fields and add them to the output string */
       

        /* iterate over all methods and add them to the output string */



        stringBuilder.append("\n}");

     
        return stringBuilder.toString();
    }

    public String getClassInfo(Class<?> clazz) {
        StringBuilder stringBuilder = new StringBuilder();

        /* implement getClassInfo() */


        return stringBuilder.toString();
    }

    public String getFieldInfo(Field field) {
        StringBuilder stringBuilder = new StringBuilder();

        /* implement getFieldInfo() */



        return stringBuilder.toString();
    }

    public String getConstructorInfo(Constructor<?> constructor) {
        StringBuilder stringBuilder = new StringBuilder();

        /* implement getConstructorInfo() */


        /* return final string */
        return stringBuilder.toString();
    }

    public String getMethodInfo(Method method) {
        StringBuilder stringBuilder = new StringBuilder();

        /* implement getMethodInfo() */


        return stringBuilder.toString();
    }

}