Revert #120 "Prevent variable nullification on later imports"

RELEASE-NOTES.md

@@ -3,7 +3,6 @@
 * #114 %load magic does not recognize notebooks
 * #115 "%load" magic should not be adding extensions to file names
 * #118 Exception stack trace truncated — cause chain not fully reported
-* #119 Variable nullification on later imports
 
 ## 1.0-a7
 

jjava-distro/src/test/java/org/dflib/jjava/distro/KernelExecutionIT.java

@@ -5,6 +5,7 @@
 
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.matchesRegex;
 import static org.hamcrest.Matchers.not;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
@@ -15,11 +16,36 @@ public class KernelExecutionIT extends ContainerizedKernelCase {
      */
     @Test
     public void variableSurvivesLaterImports() throws Exception {
-        String snippet = "%load " + CONTAINER_RESOURCES + "/nullifying_import.jshell";
+        String snippet = String.join("\n",
+                "%maven com.fasterxml.jackson.core:jackson-databind:2.21.2",
+                "import com.fasterxml.jackson.databind.*;",
+                "var om = new ObjectMapper().findAndRegisterModules();",
+                "import com.fasterxml.jackson.databind.node.*; import com.fasterxml.jackson.databind.type.*;",
+                "om.getClass().getName()"
+        );
+        Container.ExecResult snippetResult = executeInKernel(snippet);
+
+        assertEquals(0, snippetResult.getExitCode(), snippetResult.getStdout());
+        assertThat(snippetResult.getStdout(), containsString("com.fasterxml.jackson.databind.ObjectMapper"));
+        assertThat(snippetResult.getStdout(), not(matchesRegex(".*(at |\\|).*")));
+    }
+
+    /**
+     * @see <a href="https://github.com/dflib/jjava/issues/119#issuecomment-4754144547">#119</a>
+     */
+    @Test
+    public void variableRedeclarationUsesLatestValue() throws Exception {
+        String snippet = String.join("\n",
+                "int v = 1;",
+                "v",
+                "float v = 2.4f;",
+                "v"
+        );
 
         Container.ExecResult snippetResult = executeInKernel(snippet);
 
         assertEquals(0, snippetResult.getExitCode(), snippetResult.getStdout());
-        assertThat(snippetResult.getStdout(), not(containsString("|")));
+        assertThat(snippetResult.getStdout(), containsString("Out[2]: 1"));
+        assertThat(snippetResult.getStdout(), containsString("Out[4]: 2.4"));
     }
 }

jjava-kernel/src/main/java/org/dflib/jjava/kernel/execution/JJavaExecutionControl.java

@@ -76,11 +76,6 @@ public void stop() {
         executor.shutdownNow();
     }
 
-    @Override
-    public void redefine(ClassBytecodes[] cbcs) {
-        loaderDelegate.classesRedefined(cbcs);
-    }
-
     public Object takeResult(String id) {
         Object result = this.results.remove(id);
         if (result == null) {