### Question:
GenericValidatingPackager extends GenericPackager implements ISOValidator { public ISOComponent validate(ISOComponent m) throws ISOException { LogEvent evt = new LogEvent( this, "validate" ); try { ISOComponent c; Map<Object,ISOComponent> fields = m.getChildren(); for (ISOValidator val :fvlds) { if ( (c=fields.get (((ISOFieldValidator) val).getFieldId())) != null ){ try { m.set( val.validate( c ) ); } catch ( ISOVException e ) { if ( !e.treated() ) { m.set( e.getErrComponent() ); e.setTreated( true ); } evt.addMessage( "Component Validation Error." ); throw e; } } } try { for (ISOBaseValidator mval :mvlds) m = mval.validate( m ); } catch (ISOVException ex) { evt.addMessage( "Component Validation Error." ); throw ex; } return m; } finally { Logger.log( evt ); } } GenericValidatingPackager(  );  GenericValidatingPackager( String fileName );  GenericValidatingPackager(InputStream stream); void readFile(String filename); void setMsgValidator( ISOBaseValidator[] msgVlds ); void setFieldValidator( ISOFieldValidator[] fvlds ); ISOComponent validate(ISOComponent m);  }### Answer:
@Test public void testValidateThrowsNullPointerException1() throws Throwable { try { new GenericValidatingPackager().validate(null); fail("Expected NullPointerException to be thrown"); } catch (NullPointerException ex) { if (isJavaVersionAtMost(JAVA_14)) { assertNull(ex.getMessage(), "ex.getMessage()"); } else { assertEquals("Cannot invoke \"org.jpos.iso.ISOComponent.getChildren()\" because \"m\" is null", ex.getMessage(), "ex.getMessage()"); } } }