session context was:(profile=epp.package.jee, phase=org.eclipse.equinox.internal.p2.engine.phases.Collect, operand=, action=).
Unable to read repository at http://subclipse.tigris.org/update_1.6.x/features/com.collabnet.subversion.merge.feature_2.2.4.jar.
Read timed out
解决方法：
1.找到你Eclipse的eclipse.ini文件
2.添加：-Dsun.net.client.defaultReadTimeout=30000
An error occurred while collecting items to be installed
session context was:(profile=epp.package.jee, phase=org.eclipse.equinox.internal.p2.engine.phases.Collect, operand=, action=).
Unable to read repository at http://subclipse.tigris.org/update_1.6.x/features/com.collabnet.subversion.merge.feature_2.2.4.jar.
SOCKS : authentication failed
可能是vpn打开了的原因
添加：-Dsun.net.client.defaultReadTimeout=30000