First, you'll need to upgrade to JDK 1.8 or higher. Spring3.0 start, Spring source using github hosting, network no longer provide official download link. You can go on their own github website.
This thematic analysis using Spring 5.0.2 version, available for download address here: https://github.com/spring-projects/spring-framework/archive/v5.0.2.RELEASE.zip .