Radical Indonesian cleric Abu Bakar Bashir walked out of a Jakarta jail on Wednesday after serving time for links to the 2002 Bali bombings, calling on jubilant supporters to join forces for the spread of Islamic law.Australia’s Prime Minister John Howard said millions of his citizens would be extremely disappointed because of the release and a US embassy spokesman said there was cause for concern.Wearing his trademark white skullcap and red-and-white checked shawl as he emerged from prison, a smiling Bashir said: ‘‘Let us strengthen Islamic brotherhood. We strengthen our unity for one aim—that is Islamic sharia (law).’’Indonesia and other nations that ‘‘have been in darkness’’ could be saved by adherence to Islamist precepts, he said. Indonesia is the world’s most populous Muslim nation.Seen by the West as the spiritual head of the al Qaeda-linked Jemaah Islamiah (JI) regional militant network, Bashir was convicted of being part of a conspiracy behind the Bali bombings that killed 202 people, many of them Australian tourists.