test/hotspot/jtreg/runtime/testlibrary/ClassUnloadCommon.java

 /*
  * To use ClassUnloadCommon from a sub-process, see hotspot/test/runtime/logging/ClassLoadUnloadTest.java
  * for an example.
  */
 
+
 import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
 import java.net.MalformedURLException;
 import java.net.URL;
 import java.net.URLClassLoader;
 import java.nio.file.Path;
 import java.nio.file.Paths;

@@ -102,6 +105,24
             return path.toUri().toURL();
         } catch (MalformedURLException e) {
             throw new RuntimeException(e);
         }
     }
+
+    // Get data for pre-compiled class file to load.
+    public static byte[] getClassData(String name) {
+        try {
+           String TempName = name.replaceAll("\\.", "/");
+           String currentDir = System.getProperty("test.classes");
+           String filename = currentDir + File.separator + TempName + ".class";
+           System.out.println("filename is " + filename);
+           FileInputStream fis = new FileInputStream(filename);
+           byte[] b = new byte[5000];
+           int cnt = fis.read(b, 0, 5000);
+           byte[] c = new byte[cnt];
+           for (int i=0; i<cnt; i++) c[i] = b[i];
+              return c;
+        } catch (IOException e) {
+           return null;
+        }
+    }
 }