Java API bindings

The Java bindings make use of JNA to expose the C API in a Java friendly way. The bindings are based on work initiated by Toth Istvan.

Content

The bindings are articulated around a few classes in the org/libvirt package, notably the Connect, Domain and Network ones. Functions in the C API taking virConnectPtr, virDomainPtr or virNetworkPtr as their first argument usually become methods for the classes, their name is just stripped from the virConnect or virDomain(Get) prefix and the first letter gets converted to lower case, for example the C functions: 

int virConnectNumOfDomains (virConnectPtr conn);
int virDomainSetMaxMemory (virDomainPtr domain, unsigned long memory);

become 

virConn.numOfDomains()
virDomain.setMaxMemory(long memory)

There is of course some functions where the mapping is less direct and using extra classes to map complex arguments. The Javadoc is available online or as part of a separate libvirt-java-javadoc package.

So let's look at a simple example inspired from the test.java test found in src in the source tree: 

import org.libvirt.*;
public class minitest {
    public static void main(String[] args) {
        Connect conn=null;
        try{
            conn = new Connect("test:///default", true);
        } catch (LibvirtException e) {
            System.out.println("exception caught:"+e);
            System.out.println(e.getError());
        }
        try{
            Domain testDomain=conn.domainLookupByName("test");
            System.out.println("Domain:" + testDomain.getName() + " id " +
                               testDomain.getID() + " running " +
                               testDomain.getOSType());
        } catch (LibvirtException e) {
            System.out.println("exception caught:"+e);
            System.out.println(e.getError());
        }
    }
}

There is not much to comment about it, it really is a straight mapping from the C API, the only points to notice are: