Replace EasyMock dependency with Mockito and re-pin Bazel deps

java/core/BUILD

diff --git a/java/core/BUILD b/java/core/BUILD
index cf4ae7c..011fb1c 100644
--- a/java/core/BUILD
+++ b/java/core/BUILD
@@ -281,7 +281,7 @@
         "@maven//:com_google_guava_guava",
         "@maven//:com_google_truth_truth",
         "@maven//:junit_junit",
-        "@maven//:org_easymock_easymock",
+        "@maven//:org_mockito_mockito_core",
     ],
 )
 
@@ -408,6 +408,6 @@
         ":test_util_lite",
         "@maven//:com_google_truth_truth",
         "@maven//:junit_junit",
-        "@maven//:org_easymock_easymock",
+        "@maven//:org_mockito_mockito_core",
     ],
 )