private void runBuild()

in src/main/org/apache/tools/ant/Main.java [723:848]
102 lines of code
23 McCabe index (conditional complexity)

    private void runBuild(final ClassLoader coreLoader) throws BuildException {

        if (!readyToRun) {
            return;
        }

        final ArgumentProcessorRegistry processorRegistry = ArgumentProcessorRegistry.getInstance();

        for (final ArgumentProcessor processor : processorRegistry.getProcessors()) {
            final List<String> extraArgs = extraArguments.get(processor.getClass());
            if (extraArgs != null) {
                if (processor.handleArg(extraArgs)) {
                    return;
                }
            }
        }

        final Project project = new Project();
        project.setCoreLoader(coreLoader);

        Throwable error = null;

        try {
            addBuildListeners(project);
            addInputHandler(project);

            final PrintStream savedErr = System.err;
            final PrintStream savedOut = System.out;
            final InputStream savedIn = System.in;
            try {
                if (allowInput) {
                    project.setDefaultInputStream(System.in);
                }
                System.setIn(new DemuxInputStream(project));
                System.setOut(new PrintStream(new DemuxOutputStream(project, false)));
                System.setErr(new PrintStream(new DemuxOutputStream(project, true)));


                if (!projectHelp) {
                    project.fireBuildStarted();
                }

                // set the thread priorities
                if (threadPriority != null) {
                    try {
                        project.log("Setting Ant's thread priority to "
                                + threadPriority, Project.MSG_VERBOSE);
                        Thread.currentThread().setPriority(threadPriority);
                    } catch (final SecurityException swallowed) {
                        //we cannot set the priority here.
                        project.log("A security manager refused to set the -nice value");
                    }
                }

                setProperties(project);

                project.setKeepGoingMode(keepGoingMode);
                if (proxy) {
                    //proxy setup if enabled
                    final ProxySetup proxySetup = new ProxySetup(project);
                    proxySetup.enableProxies();
                }

                for (final ArgumentProcessor processor : processorRegistry.getProcessors()) {
                    final List<String> extraArgs = extraArguments.get(processor.getClass());
                    if (extraArgs != null) {
                        processor.prepareConfigure(project, extraArgs);
                    }
                }

                ProjectHelper.configureProject(project, buildFile);

                for (final ArgumentProcessor processor : processorRegistry.getProcessors()) {
                    final List<String> extraArgs = extraArguments.get(processor.getClass());
                    if (extraArgs != null) {
                        if (processor.handleArg(project, extraArgs)) {
                            return;
                        }
                    }
                }

                if (projectHelp) {
                    printDescription(project);
                    printTargets(project, msgOutputLevel > Project.MSG_INFO,
                            msgOutputLevel > Project.MSG_VERBOSE);
                    return;
                }

                // make sure that we have a target to execute
                if (targets.isEmpty()) {
                    if (project.getDefaultTarget() != null) {
                        targets.addElement(project.getDefaultTarget());
                    }
                }

                project.executeTargets(targets);
            } finally {
                System.setOut(savedOut);
                System.setErr(savedErr);
                System.setIn(savedIn);
            }
        } catch (final RuntimeException | Error exc) {
            error = exc;
            throw exc;
        } finally {
            if (!projectHelp) {
                try {
                    project.fireBuildFinished(error);
                } catch (final Throwable t) {
                    // yes, I know it is bad style to catch Throwable,
                    // but if we don't, we lose valuable information
                    System.err.println("Caught an exception while logging the"
                                       + " end of the build.  Exception was:");
                    t.printStackTrace(); //NOSONAR
                    if (error != null) {
                        System.err.println("There has been an error prior to"
                                           + " that:");
                        error.printStackTrace(); //NOSONAR
                    }
                    throw new BuildException(t); //NOSONAR
                }
            } else if (error != null) {
                project.log(error.toString(), Project.MSG_ERR);
            }
        }
    }