code: protected <T> T getParameterValue(MavenProject project, String parameter, Class<T> asType,
  			MojoExecution mojoExecution, IProgressMonitor monitor, T defaultValue) throws CoreException {
  		T value = getParameterValue(project, parameter, asType, mojoExecution, monitor);
  		if (value == null) {
  			value = defaultValue;
  		}
  		return value;
  	}
docs: Replies the configuration value.
  
  @param <T> - the expected type.
  @param project the project.
  @param parameter the parameter name.
  @param asType the expected type.
  @param mojoExecution the mojo execution.
  @param monitor the monitor.
  @param defaultValue the default value.
  @return the value of the parameter.
  @throws CoreException if cannot read the value.