問題：安裝失敗，報如下錯誤：
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://dist.springsource.com/release/TOOLS/update/3.8.4.RELEASE/e4.5/plugins/org.eclipse.m2e.core_1.7.0.20160603-1933.jar.
Read timed out
Unable to read repository at http://dist.springsource.com/release/TOOLS/update/3.8.4.RELEASE/e4.5/plugins/org.springframework.ide.eclipse.metadata_3.8.4.201703310634-RELEASE.jar.
Read timed out
Unable to read repository at http://dist.springsource.com/release/TOOLS/update/3.8.4.RELEASE/e4.5/plugins/org.springframework.ide.eclipse.quickfix_3.8.4.201703310634-RELEASE.jar.
Read timed out
解決辦法：
在eclipse 安裝目錄，即eclipse .exe所在目錄敲如下命令：
eclipse -application org.eclipse.equinox.p2.garbagecollector.application -profile epp.package.jee
問題分析：
出現錯誤的原因是Eclipse的更新管理P2出錯了。
p2有它的一個垃圾回收機制，之前刪除的JAR包在未被回收之前，再次重裝，系統不會做重新download的動作，但是它又找不到那個JAR包了，故而報錯。