@john I had to add this snippet to my

build.gradle

(I left in my notes as comments):

// Gradle 5.x ships with the Xmx setting too low to compile our project. Set it back to 1g, the default. Note: through
// testing, this only seemed necessary for Java 8, but not Java 11. Once we upgrade to Java 11 we may be able to remove
// this.
tasks.withType(GroovyCompile) {
    configure(groovyOptions.forkOptions) {
        jvmArgs = ['-Xms512m', '-Xmx1g']
    }
}