String concatenation in EL for dynamic ResourceBundle key

Question

I have a resource bundle with entries like these:

entry1=value1
entry2=value2
entry3=value3

In my JSF page I\'m trying to use these keys dy

Answer 1

If you're already on Servlet 3.1 / EL 3.0 (Tomcat 8, WildFly 8, GlassFish 4, etc), make use of new EL 3.0 += operator:

If you're only on Servlet 3.0 / EL 2.2 (Tomcat 7, JBoss AS 6/7, GlassFish 3, etc), make use of new EL 2.2 ability to directly invoke methods such as String#concat():

If you're even not on Servlet 3.0 / EL 2.2 yet, make use of to create another variable with the desired EL expression inlined: