Below is the error I am getting
An error occurred while collecting items to be installed
Unable to read repository at http://www.objectaid.net/update/plugins/com.objectaid.uml_1.1.10.jar.
Premature end of Content-Length delimited message body (expected: 1107319; received: 367016
session context was:(profile=epp.package.jee, phase=org.eclipse.equinox.internal.p2.engine.phases.Collect, operand=, action=).
I found a solution at https://mcuoneclipse.com/2015/06/15/workaround-for-installing-software-has-encountered-a-problem-in-eclipse/.
I unchecked the option to Contact all update sites during install to find required software in the Available Software menu and it worked: