Set awt headless by default

src/main/java/com/assertthat/selenium_shutterbug/core/Configurations.java

@@ -0,0 +1,29 @@
+/*
+ *  Copyright (c) 2016, Glib Briia  <a href="mailto:glib.briia@assertthat.com">Glib Briia</a>
+ *  Distributed under the terms of the MIT License
+ */
+
+package com.assertthat.selenium_shutterbug.core;
+
+import com.assertthat.selenium_shutterbug.utils.web.Browser;
+import com.assertthat.selenium_shutterbug.utils.web.Coordinates;
+import org.openqa.selenium.By;
+import org.openqa.selenium.WebDriver;
+import org.openqa.selenium.WebElement;
+import org.openqa.selenium.support.ui.ExpectedCondition;
+
+import java.util.function.Function;
+
+public class Configurations {
+    /**
+     * by default Shutterbug sets java.awt.headless=true
+     * to avoid exception "Could not initialize class sun.awt.X11GraphicsEnvironment"
+     * Method is to delete already set property
+     */
+    public Configurations headless(boolean isHeadless) {
+        if (!isHeadless) {
+            System.clearProperty("java.awt.headless");
+        }
+        return this;
+    }
+}

src/main/java/com/assertthat/selenium_shutterbug/core/Shutterbug.java

@@ -27,6 +27,10 @@ private Shutterbug() {
 
     }
 
+    static {
+        System.setProperty("java.awt.headless", "true");
+    }
+
     /**
      * Make screenshot of the viewport only.
      * To be used when screenshotting the page
@@ -452,4 +456,8 @@ public static PageSnapshot shootFrame(WebDriver driver, String frameId) {
         WebElement frame = driver.findElement(By.id(frameId));
         return shootFrame(driver, frame, CaptureElement.VIEWPORT, true);
     }
+
+    public static Configurations configure() {
+        return new Configurations();
+    }
 }