Document required Java versions for building or using WALA

README-Gradle.md

@@ -16,6 +16,14 @@ project-level Gradle caches will make incremental rebuilds much
 faster.  Rerunning `./gradlew assemble processTestResources` with a
 warm cache in an already-built tree takes under three seconds.
 
+WALA components are built using a mix of Java 11 and Java 17.  Gradle
+will [download suitable JDKs
+automatically](https://docs.gradle.org/current/userguide/toolchains.html#sec:provisioning)
+if they are not already [locally
+installed](https://docs.gradle.org/current/userguide/toolchains.html#sec:auto_detection)
+or
+[custom-configured](https://docs.gradle.org/current/userguide/toolchains.html#sec:custom_loc).
+
 ## Eclipse
 
 ### One-Time Eclipse Configuration

README.md

@@ -82,6 +82,13 @@ list](http://sourceforge.net/p/wala/mailman/), [ask a question on
 Gitter](https://gitter.im/WALAHelp/Lobby), or [open an
 issue](https://github.com/wala/WALA/issues).
 
+## Required Java Versions
+
+Most components of each [official WALA
+release](https://github.com/wala/WALA/releases) are built for use with
+Java 11 or newer.  However, components that use Eclipse require at
+least Java 17.
+
 ## Building from Source
 
 WALA uses Gradle as its build system.  If you intend to modify or