Program: 90714
Project: 90714
Buggy source:
/** 
 * Factory method for creating a connection source within the plugin manager.
 * @param className The name of a public class that contains a static method capable of returning either a{@link DataSource} or a {@link Connection}.
 * @param methodName The name of the public static method on the aforementioned class that returns the data sourceor connection. If this method returns a  {@link Connection}, it should return a new connection every call.
 * @return the created connection source.
 */
@PluginFactory public static FactoryMethodConnectionSource createConnectionSource(@PluginAttr("String_Node_Str") final String className,@PluginAttr("String_Node_Str") final String methodName){
  if (Strings.isEmpty(className) || Strings.isEmpty(methodName)) {
    LOGGER.error("String_Node_Str");
    return null;
  }
  final Method method;
  try {
    final Class<?> factoryClass=Class.forName(className);
    method=factoryClass.getMethod(methodName);
  }
 catch (  final Exception e) {
    LOGGER.error(e.toString(),e);
    return null;
  }
  final Class<?> returnType=method.getReturnType();
  String returnTypeString=returnType.getName();
  DataSource dataSource;
  if (returnType == DataSource.class) {
    try {
      dataSource=(DataSource)method.invoke(null);
      returnTypeString+="String_Node_Str" + dataSource + "String_Node_Str";
    }
 catch (    final Exception e) {
      LOGGER.error(e.toString(),e);
      return null;
    }
  }
 else   if (returnType == Connection.class) {
    dataSource=new DataSource(){
      @Override public Connection getConnection() throws SQLException {
        try {
          return (Connection)method.invoke(null);
        }
 catch (        final Exception e) {
          throw new SQLException("String_Node_Str",e);
        }
      }
      @Override public Connection getConnection(      final String username,      final String password) throws SQLException {
        throw new UnsupportedOperationException();
      }
      @Override public int getLoginTimeout() throws SQLException {
        throw new UnsupportedOperationException();
      }
      @Override public PrintWriter getLogWriter() throws SQLException {
        throw new UnsupportedOperationException();
      }
      @Override @SuppressWarnings("String_Node_Str") public java.util.logging.Logger getParentLogger(){
        throw new UnsupportedOperationException();
      }
      @Override public boolean isWrapperFor(      final Class<?> iface) throws SQLException {
        return false;
      }
      @Override public void setLoginTimeout(      final int seconds) throws SQLException {
        throw new UnsupportedOperationException();
      }
      @Override public void setLogWriter(      final PrintWriter out) throws SQLException {
        throw new UnsupportedOperationException();
      }
      @Override public <T>T unwrap(      final Class<T> iface) throws SQLException {
        return null;
      }
    }
;
  }
 else {
    LOGGER.error("String_Node_Str",className,methodName,returnType.getName());
    return null;
  }
  return new FactoryMethodConnectionSource(dataSource,className,methodName,returnTypeString);
}

Fixed version (ground truth):
/** 
 * Factory method for creating a connection source within the plugin manager.
 * @param className The name of a public class that contains a static method capable of returning either a{@link DataSource} or a {@link Connection}.
 * @param methodName The name of the public static method on the aforementioned class that returns the data sourceor connection. If this method returns a  {@link Connection}, it should return a new connection every call.
 * @return the created connection source.
 */
@PluginFactory public static FactoryMethodConnectionSource createConnectionSource(@PluginAttr("String_Node_Str") final String className,@PluginAttr("String_Node_Str") final String methodName){
  if (Strings.isEmpty(className) || Strings.isEmpty(methodName)) {
    LOGGER.error("String_Node_Str");
    return null;
  }
  final Method method;
  try {
    final Class<?> factoryClass=Class.forName(className);
    method=factoryClass.getMethod(methodName);
  }
 catch (  final Exception e) {
    LOGGER.error(e.toString(),e);
    return null;
  }
  final Class<?> returnType=method.getReturnType();
  String returnTypeString=returnType.getName();
  DataSource dataSource;
  if (returnType == DataSource.class) {
    try {
      dataSource=(DataSource)method.invoke(null);
      returnTypeString+="String_Node_Str" + dataSource + "String_Node_Str";
    }
 catch (    final Exception e) {
      LOGGER.error(e.toString(),e);
      return null;
    }
  }
 else   if (returnType == Connection.class) {
    dataSource=new DataSource(){
      @Override public Connection getConnection() throws SQLException {
        try {
          return (Connection)method.invoke(null);
        }
 catch (        final Exception e) {
          throw new SQLException("String_Node_Str",e);
        }
      }
      @Override public Connection getConnection(      final String username,      final String password) throws SQLException {
        throw new UnsupportedOperationException();
      }
      @Override public int getLoginTimeout() throws SQLException {
        throw new UnsupportedOperationException();
      }
      @Override public PrintWriter getLogWriter() throws SQLException {
        throw new UnsupportedOperationException();
      }
      @SuppressWarnings("String_Node_Str") public java.util.logging.Logger getParentLogger(){
        throw new UnsupportedOperationException();
      }
      @Override public boolean isWrapperFor(      final Class<?> iface) throws SQLException {
        return false;
      }
      @Override public void setLoginTimeout(      final int seconds) throws SQLException {
        throw new UnsupportedOperationException();
      }
      @Override public void setLogWriter(      final PrintWriter out) throws SQLException {
        throw new UnsupportedOperationException();
      }
      @Override public <T>T unwrap(      final Class<T> iface) throws SQLException {
        return null;
      }
    }
;
  }
 else {
    LOGGER.error("String_Node_Str",className,methodName,returnType.getName());
    return null;
  }
  return new FactoryMethodConnectionSource(dataSource,className,methodName,returnTypeString);
}