* Trading companies, resource-related shares outperform * Nikkei nears major resistance levels such as 75-day MA * Low trading volume raises doubts about strength of rally * Expectations of easing by c.banks continue to support market * Lawson falls from 4-yr high after earnings, Parco jumps By Hideyuki Sano TOKYO, July 4 (Reuters) - Japan's Nikkei share average finished at a two-month high on Wednesday, driven by energy and resource companies following a rise in oil prices and bolstered by improved risk appetite amid expectations that central banks will act to support flagging global growth.