WhatJDK

Find out what JDK compatibility a Jar has, even one with embedded Jars!

Usage

./whatjdk/whatjdk some.war
some.war:WEB-INF/lib/xml-apis-1.4.01.jar contains classes compatible with Java1.1
some.war contains classes compatible with Java1.6

Requirements

Java Runtime and Maven if you plan on building the jar (probable)

Maven Plugin

<build>
    <plugins>
        ...
        <plugin>
            <groupId>com.iodesystems</groupId>
            <artifactId>whatjdk-maven-plugin</artifactId>
            <version>${project.version}</version>
            <configuration>
                <allowedJdkVersions>Java1.4,Java1.5,Java1.6</allowedJdkVersions>
            </configuration>
            <executions>
                <execution>
                    <goals>
                        <goal>verify</goal>
                    </goals>
                </execution>
            </executions>
        </plugin>
        ...
    </plugins>
</build>