PropertiesLauncher requires spring-core on the classpath

[maxxedev]

Uber jar created by spring-boot-maven-plugin sometimes requires that the application depends on spring-framework.

1. PropertiesLauncher imports Assert from spring-framework, and can sometimes fail.

2. JarModeLauncher imports two spring-framework classes, and always fails. This means layered jar cannot be used without spring-framework.

It is perhaps reasonable to assume that spring-boot-maven-plugin is used only in spring-boot apps which should have spring-framework on the classpath. Nonetheless, it'd be nice to eliminate these dependencies so that the plugin can be used for non-spring apps too.

[wilkinsona]

Thanks for the suggestion, but we're happy with spring-core being required here. JarModeLauncher in particular would add quite a bit of extra complexity without spring-core as it uses SpringFactoriesLoader.

[wilkinsona]

On second thought, let's consider this for PropertiesLauncher. It has no dependency on spring-core in 2.1 (and earlier I believe). The use of Assert was introduced in this commit.

[philwebb]

+1 for updating PropertiesLauncher. The JarModeLauncher was an intentional design decision since we wanted to lean on spring.factories.