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

*** 28,37 ****
--- 28,38 ----
  import java.io.InputStream;
  import java.io.IOException;
  import java.io.UncheckedIOException;
  import java.io.File;
  import java.lang.reflect.Constructor;
+ import java.lang.reflect.InvocationTargetException;
  import java.net.URL;
  import java.security.AccessController;
  import java.security.AccessControlContext;
  import java.security.CodeSource;
  import java.security.PrivilegedAction;
*** 1865,1875 ****
       * instance is then created using this constructor with the default system
       * class loader as the parameter.  The resulting class loader is defined
       * to be the system class loader. During construction, the class loader
       * should take great care to avoid calling {@code getSystemClassLoader()}.
       * If circular initialization of the system class loader is detected then
!      * an unspecified error or exception is thrown.
       *
       * @implNote The system property to override the system class loader is not
       * examined until the VM is almost fully initialized. Code that executes
       * this method during startup should take care not to cache the return
       * value until the system is fully initialized.
--- 1866,1876 ----
       * instance is then created using this constructor with the default system
       * class loader as the parameter.  The resulting class loader is defined
       * to be the system class loader. During construction, the class loader
       * should take great care to avoid calling {@code getSystemClassLoader()}.
       * If circular initialization of the system class loader is detected then
!      * an {@code IllegalStateException} is thrown.
       *
       * @implNote The system property to override the system class loader is not
       * examined until the VM is almost fully initialized. Code that executes
       * this method during startup should take care not to cache the return
       * value until the system is fully initialized.
*** 1916,1927 ****
              case 1:
              case 2:
                  // the system class loader is the built-in app class loader during startup
                  return getBuiltinAppClassLoader();
              case 3:
!                 String msg = "getSystemClassLoader should only be called after VM booted";
!                 throw new InternalError(msg);
              case 4:
                  // system fully initialized
                  assert VM.isBooted() && scl != null;
                  SecurityManager sm = System.getSecurityManager();
                  if (sm != null) {
--- 1917,1928 ----
              case 1:
              case 2:
                  // the system class loader is the built-in app class loader during startup
                  return getBuiltinAppClassLoader();
              case 3:
!                 String msg = "getSystemClassLoader cannot be called during the system class loader instantiation";
!                 throw new IllegalStateException(msg);
              case 4:
                  // system fully initialized
                  assert VM.isBooted() && scl != null;
                  SecurityManager sm = System.getSecurityManager();
                  if (sm != null) {
*** 1967,1977 ****
                  // custom class loader is only supported to be loaded from unnamed module
                  Constructor<?> ctor = Class.forName(cn, false, builtinLoader)
                                             .getDeclaredConstructor(ClassLoader.class);
                  scl = (ClassLoader) ctor.newInstance(builtinLoader);
              } catch (Exception e) {
!                 throw new Error(e);
              }
          } else {
              scl = builtinLoader;
          }
          return scl;
--- 1968,1985 ----
                  // custom class loader is only supported to be loaded from unnamed module
                  Constructor<?> ctor = Class.forName(cn, false, builtinLoader)
                                             .getDeclaredConstructor(ClassLoader.class);
                  scl = (ClassLoader) ctor.newInstance(builtinLoader);
              } catch (Exception e) {
!                 Throwable cause = e;
!                 if (e instanceof InvocationTargetException) {
!                     cause = e.getCause();
!                     if (cause instanceof RuntimeException) {
!                         throw (RuntimeException) cause;
!                     }
!                 }
!                 throw new Error(cause.getMessage(), cause);
              }
          } else {
              scl = builtinLoader;
          }
          return scl;