If you have web development knowledge, then scripting should be really easy for you pick up.
Firstly, you want to pick out an IDE; IntelliJ, Eclipse
Once you've installed Java JDK 8.0+, open up your IDE and create a new project. For now you should ignore basic scripting and learn to do simple tasks in raw java such as; hello world, printing data types and objects, understanding of methods and their return types, parameters, fields, and constructors, and most importantly, understanding object references in memory. Once you're able to make a basic java application that can successfully use the core basics of Java, only then should you attempt to make a basic script. Understanding object references and their return types is going to save you a lot of headache when you're first starting to script.
keywords
primitive data types
method structure parameters fields constructors
That's just to scratch the surface, but you can write a basic script with only knowledge of keywords, primitives, and method structure. The rest is only needed for more complex scripts.
If you're a visual learner, then I suggest watching Bucky's Java tutorial series on YouTube up to at least video 35 for a good grasp on how to make an intermediate script.
Good luck