Move to bazel 7 and turn down support for bazel 6.

Migrate all tests to run on bazel 7 and fix errors that came up in the process. 30.x will no longer guarantee support for bazel 6.
#test-continuous

PiperOrigin-RevId: 703590770

WORKSPACE

diff --git a/WORKSPACE b/WORKSPACE
index ace370c..3716b13 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -24,6 +24,10 @@
 
 protobuf_extra_deps()
 
+load("@bazel_features//:deps.bzl", "bazel_features_deps")
+
+bazel_features_deps()
+
 load("@rules_python//python:repositories.bzl", "py_repositories")
 
 py_repositories()
@@ -98,6 +102,12 @@
 
 apple_support_dependencies()
 
+load("@rules_java//java:repositories.bzl", "rules_java_dependencies", "rules_java_toolchains")
+
+rules_java_dependencies()
+
+rules_java_toolchains()
+
 load("@rules_cc//cc:repositories.bzl", "rules_cc_dependencies")
 
 rules_cc_dependencies()
@@ -241,6 +251,7 @@
 # For testing runtime against old gencode from a previous major version.
 http_archive(
     name = "com_google_protobuf_v25.0",
+    integrity = "sha256-e+7ZxRHWMs/3wirACU3Xcg5VAVMDnV2n4Fm8zrSIR0o=",
     strip_prefix = "protobuf-25.0",
     url = "https://github.com/protocolbuffers/protobuf/releases/download/v25.0/protobuf-25.0.tar.gz",
 )