You must be young. Java was not always distributed like this, and although it was "open source" few people compiled it, and the JRE and JDK was distributed by Sun (then Oracle) primarily through a user interactive web UI. The OpenJDK existed alongside this for some time, but then supplanted the proprietary binaries. That was a relief because it meant Java was actually (not just theoretically) open source now, which meant it was safe from deprecation, disablement, and all the other negative aspects of control that come with de facto proprietary software.