Index: trunk/src/org/openstreetmap/josm/actions/ValidateAction.java
===================================================================
--- trunk/src/org/openstreetmap/josm/actions/ValidateAction.java	(revision 17614)
+++ trunk/src/org/openstreetmap/josm/actions/ValidateAction.java	(revision 17616)
@@ -6,24 +6,15 @@
 import java.awt.event.ActionEvent;
 import java.awt.event.KeyEvent;
-import java.io.IOException;
-import java.util.ArrayList;
 import java.util.Collection;
-import java.util.List;
 import java.util.Optional;
 
 import org.openstreetmap.josm.data.osm.OsmPrimitive;
-import org.openstreetmap.josm.data.preferences.sources.ValidatorPrefHelper;
 import org.openstreetmap.josm.data.validation.OsmValidator;
 import org.openstreetmap.josm.data.validation.Test;
-import org.openstreetmap.josm.data.validation.TestError;
+import org.openstreetmap.josm.data.validation.ValidationTask;
 import org.openstreetmap.josm.data.validation.util.AggregatePrimitivesVisitor;
 import org.openstreetmap.josm.gui.MainApplication;
 import org.openstreetmap.josm.gui.MapFrame;
-import org.openstreetmap.josm.gui.PleaseWaitRunnable;
-import org.openstreetmap.josm.gui.layer.ValidatorLayer;
-import org.openstreetmap.josm.gui.util.GuiHelper;
-import org.openstreetmap.josm.io.OsmTransferException;
 import org.openstreetmap.josm.tools.Shortcut;
-import org.xml.sax.SAXException;
 
 /**
@@ -104,82 +95,3 @@
     }
 
-    /**
-     * Asynchronous task for running a collection of tests against a collection of primitives
-     */
-    static class ValidationTask extends PleaseWaitRunnable {
-        private Collection<Test> tests;
-        private final Collection<OsmPrimitive> validatedPrimitives;
-        private final Collection<OsmPrimitive> formerValidatedPrimitives;
-        private boolean canceled;
-        private List<TestError> errors;
-
-        /**
-         * Constructs a new {@code ValidationTask}
-         * @param tests  the tests to run
-         * @param validatedPrimitives the collection of primitives to validate.
-         * @param formerValidatedPrimitives the last collection of primitives being validates. May be null.
-         */
-        ValidationTask(Collection<Test> tests, Collection<OsmPrimitive> validatedPrimitives,
-                Collection<OsmPrimitive> formerValidatedPrimitives) {
-            super(tr("Validating"), false /*don't ignore exceptions */);
-            this.validatedPrimitives = validatedPrimitives;
-            this.formerValidatedPrimitives = formerValidatedPrimitives;
-            this.tests = tests;
-        }
-
-        @Override
-        protected void cancel() {
-            this.canceled = true;
-        }
-
-        @Override
-        protected void finish() {
-            if (canceled) return;
-
-            // update GUI on Swing EDT
-            //
-            GuiHelper.runInEDT(() -> {
-                MapFrame map = MainApplication.getMap();
-                map.validatorDialog.unfurlDialog();
-                map.validatorDialog.tree.setErrors(errors);
-                //FIXME: nicer way to find / invalidate the corresponding error layer
-                MainApplication.getLayerManager().getLayersOfType(ValidatorLayer.class).forEach(ValidatorLayer::invalidate);
-                if (!errors.isEmpty()) {
-                    OsmValidator.initializeErrorLayer();
-                }
-            });
-        }
-
-        @Override
-        protected void realRun() throws SAXException, IOException,
-        OsmTransferException {
-            if (tests == null || tests.isEmpty())
-                return;
-            errors = new ArrayList<>();
-            getProgressMonitor().setTicksCount(tests.size() * validatedPrimitives.size());
-            int testCounter = 0;
-            for (Test test : tests) {
-                if (canceled)
-                    return;
-                testCounter++;
-                getProgressMonitor().setCustomText(tr("Test {0}/{1}: Starting {2}", testCounter, tests.size(), test.getName()));
-                test.setBeforeUpload(false);
-                test.setPartialSelection(formerValidatedPrimitives != null);
-                test.startTest(getProgressMonitor().createSubTaskMonitor(validatedPrimitives.size(), false));
-                test.visit(validatedPrimitives);
-                test.endTest();
-                errors.addAll(test.getErrors());
-                test.clear();
-            }
-            tests = null;
-            if (Boolean.TRUE.equals(ValidatorPrefHelper.PREF_USE_IGNORE.get())) {
-                getProgressMonitor().setCustomText("");
-                getProgressMonitor().subTask(tr("Updating ignored errors ..."));
-                for (TestError error : errors) {
-                    if (canceled) return;
-                    error.updateIgnored();
-                }
-            }
-        }
-    }
 }
Index: trunk/src/org/openstreetmap/josm/data/validation/ValidationTask.java
===================================================================
--- trunk/src/org/openstreetmap/josm/data/validation/ValidationTask.java	(revision 17616)
+++ trunk/src/org/openstreetmap/josm/data/validation/ValidationTask.java	(revision 17616)
@@ -0,0 +1,96 @@
+// License: GPL. For details, see LICENSE file.
+package org.openstreetmap.josm.data.validation;
+
+import org.openstreetmap.josm.data.osm.OsmPrimitive;
+import org.openstreetmap.josm.data.preferences.sources.ValidatorPrefHelper;
+import org.openstreetmap.josm.gui.MainApplication;
+import org.openstreetmap.josm.gui.MapFrame;
+import org.openstreetmap.josm.gui.PleaseWaitRunnable;
+import org.openstreetmap.josm.gui.layer.ValidatorLayer;
+import org.openstreetmap.josm.gui.util.GuiHelper;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+import static org.openstreetmap.josm.tools.I18n.tr;
+
+/**
+ * Asynchronous task for running a collection of tests against a collection of primitives
+ */
+public class ValidationTask extends PleaseWaitRunnable {
+    private Collection<Test> tests;
+    private final Collection<OsmPrimitive> validatedPrimitives;
+    private final Collection<OsmPrimitive> formerValidatedPrimitives;
+    private boolean canceled;
+    private List<TestError> errors;
+
+    /**
+     * Constructs a new {@code ValidationTask}
+     *
+     * @param tests                     the tests to run
+     * @param validatedPrimitives       the collection of primitives to validate.
+     * @param formerValidatedPrimitives the last collection of primitives being validates. May be null.
+     */
+    public ValidationTask(Collection<Test> tests,
+                          Collection<OsmPrimitive> validatedPrimitives,
+                          Collection<OsmPrimitive> formerValidatedPrimitives) {
+        super(tr("Validating"), false /*don't ignore exceptions */);
+        this.validatedPrimitives = validatedPrimitives;
+        this.formerValidatedPrimitives = formerValidatedPrimitives;
+        this.tests = tests;
+    }
+
+    @Override
+    protected void cancel() {
+        this.canceled = true;
+    }
+
+    @Override
+    protected void finish() {
+        if (canceled) return;
+
+        // update GUI on Swing EDT
+        GuiHelper.runInEDT(() -> {
+            MapFrame map = MainApplication.getMap();
+            map.validatorDialog.unfurlDialog();
+            map.validatorDialog.tree.setErrors(errors);
+            //FIXME: nicer way to find / invalidate the corresponding error layer
+            MainApplication.getLayerManager().getLayersOfType(ValidatorLayer.class).forEach(ValidatorLayer::invalidate);
+            if (!errors.isEmpty()) {
+                OsmValidator.initializeErrorLayer();
+            }
+        });
+    }
+
+    @Override
+    protected void realRun() {
+        if (tests == null || tests.isEmpty())
+            return;
+        errors = new ArrayList<>();
+        getProgressMonitor().setTicksCount(tests.size() * validatedPrimitives.size());
+        int testCounter = 0;
+        for (Test test : tests) {
+            if (canceled)
+                return;
+            testCounter++;
+            getProgressMonitor().setCustomText(tr("Test {0}/{1}: Starting {2}", testCounter, tests.size(), test.getName()));
+            test.setBeforeUpload(false);
+            test.setPartialSelection(formerValidatedPrimitives != null);
+            test.startTest(getProgressMonitor().createSubTaskMonitor(validatedPrimitives.size(), false));
+            test.visit(validatedPrimitives);
+            test.endTest();
+            errors.addAll(test.getErrors());
+            test.clear();
+        }
+        tests = null;
+        if (Boolean.TRUE.equals(ValidatorPrefHelper.PREF_USE_IGNORE.get())) {
+            getProgressMonitor().setCustomText("");
+            getProgressMonitor().subTask(tr("Updating ignored errors ..."));
+            for (TestError error : errors) {
+                if (canceled) return;
+                error.updateIgnored();
+            }
+        }
+    }
+}