Building JDK 8 on Fedora 31 (GCC 9.2.1)

This blog lists out the steps to build JDK 8 on Fedora 31. I had some compilation problems while building it, so you may find this useful.

1. I was building the openjdk 8u, so we have to clone it from the public repo

    $ hg clone http://hg.openjdk.java.net/jdk8u/jdk8u

2. This will just bring some source and scripts which are necessary to get the actual JDK and hotspot sources.

3. To get the actual sources, run the utility shell script

    $ ./get_source.sh

4. Configure the build for your system

    $ bash configure

5. Add below options if you want debug symbols

    $ bash configure --with-debug-level=slowdebug

6. Set the environment variable to resolve the compilation errors

    $ export CFLAGS="-Wno-return-type"

7. Run the build

    $ make

Little more info

gcc version

$ gcc --version
gcc (GCC) 9.2.1 20190827 (Red Hat 9.2.1-1)
Copyright (C) 2019 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.