The capybara (Hydrochoerus hydrochaeris) is a large rodent of the genus Hydrochoerus of which the only other extant member is the lesser capybara (Hydrochoerus isthmius).
JDK is what gives the Java programming language its unique features of portability, security, simplicity, high performance, dynamism among others. With such features, it is no wonder as to why most developers opt to use Java when designing applications.
What you must have. In order to run other peoples' Java programs, you must have the JRE (Java Runtime Environment). In order to write and run your own Java programs, you must have the JDK (Java Development Kit), which is sometimes called the SDK (System Development Kit)--these are the same thing. The JDK includes the JRE, so don't get both.