Chapter 3. Code-level integration
This chapter covers
- Calling Groovy scripts from Java using JSR 223
- Calling Groovy scripts from Java using Groovy library classes
In chapter 1 I reviewed many of Java’s arguable weaknesses and drawbacks and suggested ways that Groovy might help ameliorate them. Because that chapter was intended to be introductory, I only suggested how Groovy can help, without showing a lot of code examples.
This chapter begins an examination of Java and Groovy integration in detail. In this chapter I’ll start using Groovy and Java together in fundamental ways, without worrying about frameworks or addressing any particular use case. A guide to the techniques discussed in this chapter is shown in figure 3.1.
Figure 3.1. Guide to integration features. Groovy can be accessed with Java classes alone using the JSR 223 script engine. If you are willing to add some Groovy library classes to Java, the Eval, GroovyShell, and Binding classes make working with scripts easy. The best way to combine Groovy and Java is using classes for both languages.
