Bug 114774 [javadoc location] validate does not work with ! in path
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/preferences/JavadocConfigurationBlock.java
String url= chooseJavaDocFolder();
			if (url != null) {
				fURLField.setText(url);
			}
		} else if (field == fBrowseArchive) {
			String jarPath= chooseArchive();
			if (jarPath != null) {
				fArchiveField.setText(jarPath);
			}
		} else if (field == fBrowseArchivePath) {
			String archivePath= chooseArchivePath();
			if (archivePath != null) {
				fArchivePathField.setText(archivePath);
			}		
		} else if (field == fURLRadioButton || field == fArchiveRadioButton) {
			statusChanged();							
		}
	}
	
	private void statusChanged() {
		IStatus status;
		boolean isURL= fIsForSource || fURLRadioButton.isSelected();
		if (isURL) {
			status= fURLStatus;
		} else {
			status= StatusUtil.getMoreSevere(fArchiveStatus, fArchivePathStatus);
		}
		if (!fIsForSource) {
			fBrowseArchivePath.setEnabled(!isURL && fArchiveStatus.isOK() && fArchiveField.getText().length() > 0);
		}