The Ireland Under-20s, who are coached by Allen Clarke this season, have been drawn in Pool A which will have its matches in Nagoya.
New Zealand and Argentina, whom the Irish faced at last season's Junior World Championship in Wales, will provide the main challenges again.
Then coached by Eric Elwood, the Irish side lost pool games to New Zealand (65-10 and Argentina (17-9) last June.
Elwood's charges bounced back to finish ninth overall, thanks to wins over Tonga (45-27), Italy (9-6) and Scotland (39-12).
Uruguay, who gained promotion to this tournament after winning the 2008 Junior World Trophy, are new opponents for Ireland at this level.
The opening round of matches will be played on June 5, with subsequent pool fixtures played on June 9 and June 13, before Tokyo hosts the semi-finals on June 17, with the IRB Junior World Championship final played in Tokyo on June 21.
Speaking from Japan, IRB Tournament Director Philippe Bourdarias said that he has been impressed with the Japan Rugby Football Union's level of commitment to deliver one of the best IRB age grade championships ever.
"The IRB is extremely pleased with the level of dedication and professionalism that the Japan Rugby Football Union has invested in hosting this major international rugby tournament," he said.
"This professionalism is clearly reflected in the choice of venues in four major cities, meaning that each of the 16 teams will have access to world-class playing and training facilities.
"With matches being played in Tokyo, Osaka, Fukuoka and Nagoya, the 2009 IRB Junior World Championship has the ability to engage the rugby community on a wider scale than ever before.
"The Japan Rugby Football Union is committed to growing the game in the country and an extensive dedicated legacy programme will be activated to maximise the impact of the championship."
Japan Rugby Football Union Chairman and Vice President Nobby Mashimo said that Japan has a tremendous opportunity to show to showcase rugby within the country and host a memorable and successful championship.
"I hope that many Japanese fans will take this opportunity to experience world class rugby up close and personal," he said.
"Also I hope that the legacy programme will create many opportunities for international exchange between participating teams and the Japan Rugby Community.
"We are looking forward to hosting the tournament and hope that the 16 teams will enjoy the excellent facilities and experience all that Japan has to offer on and off the pitch, including our warm hospitality and friendship."
Yoshiru Mori, President of the Japan Rugby Football Union, added: "We would like to take this opportunity of hosting this tournament to not only appeal to the world with our rugby tournament potential, but to also make it our foothold for the further promotion and development of rugby in Asia.
"We want to successfully host this memorable tournament in Japan to the enjoyment of rugby fans worldwide."
The full Junior World Championship schedule will be announced shortly.
2009 IRB JUNIOR WORLD CHAMPIONSHIP POOLS:
Pool A - New Zealand, Argentina, IRELAND, Uruguay
Pool B - England, Samoa, Scotland, Japan
Pool C - South Africa, France, Italy, Fiji
Pool D - Wales, Australia, Canada, Tonga