This comic is playing off of the concept of a “golden hammer” - a phrase used to describe a single tool or utility that someone uses in every possible situation, even if it is not the best tool for the job. It is is often expanded to state, “when all you have is a hammer, everything starts to look like a nail”, meaning that you will inevitably use your “hammer” for something it is not suited for.
The sitting-down man remarks in amazement that a small hardware device he is “hacking” on apparently runs the Java Virtual Machine - a large and complex piece of computer software used to, among other things, interpret and execute Java code. This is surprising to the man as this would be a very difficult and time-consuming task, and ultimately (in his opinion) unnecessary. He unknowingly is attributing the golden hammer effect to the device’s manufacturer by noticing that they have gone terribly out of their way to allow the use of their chosen hammer - Java.
The hatted man then walks in and replaces “hammer” and “something it is not suited for” in the aforementioned phrase with other words that the Author deemed more wacky and humorous. Another example of this could be: “when all you have is a ball-point pen, everything starts to look like a stick figure.”
