8291360: Create entry points to expose low-level class file information

Reviewed-by: dholmes, rriggs

src/java.base/share/classes/java/lang/Class.java

@@ -4668,4 +4668,34 @@ public final class Class<T> implements java.io.Serializable,
     }
 
     private native Class<?>[] getPermittedSubclasses0();
+
+    /*
+     * Return the class's major and minor class file version packed into an int.
+     * The high order 16 bits contain the class's minor version.  The low order
+     * 16 bits contain the class's major version.
+     *
+     * If the class is an array type then the class file version of its element
+     * type is returned.  If the class is a primitive type then the latest class
+     * file major version is returned and zero is returned for the minor version.
+     */
+    private int getClassFileVersion() {
+        Class<?> c = isArray() ? elementType() : this;
+        return c.getClassFileVersion0();
+    }
+
+    private native int getClassFileVersion0();
+
+    /*
+     * Return the access flags as they were in the class's bytecode, including
+     * the original setting of ACC_SUPER.
+     *
+     * If the class is an array type then the access flags of the element type is
+     * returned.  If the class is a primitive then ACC_ABSTRACT | ACC_FINAL | ACC_PUBLIC.
+     */
+    private int getClassAccessFlagsRaw() {
+        Class<?> c = isArray() ? elementType() : this;
+        return c.getClassAccessFlagsRaw0();
+    }
+
+    private native int getClassAccessFlagsRaw0();
 }