Turns out some of my Maven dependencies weren't compiled with 1.5, which caused the problem. It wasn't happening in the console because I had already set java 1.7 as default.
Fortunately, I was able to build my project using 1.7 and specifying 1.5 to run compile and execute. Here's how:
in Eclipse>Run>Run Configurations>Maven Build>New, I had this configuration:
Main Tab
Base Directory:
${project_loc}
Goals:
clean install
I just chose the JRE tab and chose and Alternate JRE, using my 1.7 SDK installation.
Next, I had to include 1.5 as source and target for the maven-compiler-plugin my pom.xml, as such:
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.0</version>
<configuration>
<encoding>ISO-8859-1</encoding>
<source>1.5</source>
<target>1.5</target>
</configuration>
</plugin>
And it works.