Fix class file version detection (#8057)

we are forcing 1.8 class file version when it's below, but we
are checking against the full version while we need to check against
the major version only

Author: jpbempel

dd-java-agent/agent-debugger/src/main/java/com/datadog/debugger/agent/DebuggerTransformer.java

@@ -422,7 +422,7 @@ private byte[] writeClassFile(
       ClassLoader loader,
       String classFilePath,
       ClassNode classNode) {
-    if (classNode.version < Opcodes.V1_8) {
+    if ((classNode.version & 0xFF) < Opcodes.V1_8) {
       // Class file version must be at least 1.8 (52)
       classNode.version = Opcodes.V1_8;
     }

dd-java-agent/agent-debugger/src/test/java/com/datadog/debugger/agent/CapturedSnapshotTest.java

@@ -66,6 +66,7 @@
 import java.lang.reflect.Modifier;
 import java.net.URISyntaxException;
 import java.net.URL;
+import java.nio.file.Paths;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
@@ -211,6 +212,24 @@ public void veryOldClassFile() throws Exception {
     assertOneSnapshot(listener);
   }
 
+  @Test
+  public void oldClass1_1() throws Exception {
+    final String CLASS_NAME = "org.apache.commons.lang.BooleanUtils"; // compiled with jdk 1.1
+    TestSnapshotListener listener = installSingleProbe(CLASS_NAME, "toBoolean", null);
+    when(config.isDebuggerVerifyByteCode()).thenReturn(true);
+    Class<?> testClass =
+        loadClass(
+            CLASS_NAME,
+            Paths.get(
+                    CapturedSnapshotTest.class
+                        .getResource("/classfiles/BooleanUtils.classfile")
+                        .toURI())
+                .toString());
+    boolean result = Reflect.onClass(testClass).call("toBoolean", Boolean.TRUE).get();
+    assertTrue(result);
+    assertOneSnapshot(listener);
+  }
+
   @Test
   public void oldJavacBug() throws Exception {
     final String CLASS_NAME = "com.datadog.debugger.classfiles.JavacBug"; // compiled with jdk 1.6