From de3b47bd60a098c88084b2e1008fb776311af59b Mon Sep 17 00:00:00 2001
From: fritzprix <dw.lee@sk.com>
Date: Fri, 26 Apr 2019 15:00:36 +0900
Subject: [PATCH] init commit

---
 .idea/compiler.xml                            |  13 +
 .idea/encodings.xml                           |   4 +
 .idea/misc.xml                                |  14 +
 .idea/uiDesigner.xml                          | 124 ++++++++
 .idea/workspace.xml                           | 286 ++++++++++++++++++
 pom.xml                                       | 123 ++++++++
 robustdns.iml                                 |   2 +
 .../doodream/robustdns/RobustDnsResolver.java |  67 ++++
 8 files changed, 633 insertions(+)
 create mode 100644 .idea/compiler.xml
 create mode 100644 .idea/encodings.xml
 create mode 100644 .idea/misc.xml
 create mode 100644 .idea/uiDesigner.xml
 create mode 100644 .idea/workspace.xml
 create mode 100644 pom.xml
 create mode 100644 robustdns.iml
 create mode 100644 src/main/java/com/doodream/robustdns/RobustDnsResolver.java

diff --git a/.idea/compiler.xml b/.idea/compiler.xml
new file mode 100644
index 0000000..aa899e4
--- /dev/null
+++ b/.idea/compiler.xml
@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="CompilerConfiguration">
+    <annotationProcessing>
+      <profile name="Maven default annotation processors profile" enabled="true">
+        <sourceOutputDir name="target/generated-sources/annotations" />
+        <sourceTestOutputDir name="target/generated-test-sources/test-annotations" />
+        <outputRelativeToContentRoot value="true" />
+        <module name="robustdns" />
+      </profile>
+    </annotationProcessing>
+  </component>
+</project>
\ No newline at end of file
diff --git a/.idea/encodings.xml b/.idea/encodings.xml
new file mode 100644
index 0000000..15a15b2
--- /dev/null
+++ b/.idea/encodings.xml
@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="Encoding" addBOMForNewFiles="with NO BOM" />
+</project>
\ No newline at end of file
diff --git a/.idea/misc.xml b/.idea/misc.xml
new file mode 100644
index 0000000..4b661a5
--- /dev/null
+++ b/.idea/misc.xml
@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ExternalStorageConfigurationManager" enabled="true" />
+  <component name="MavenProjectsManager">
+    <option name="originalFiles">
+      <list>
+        <option value="$PROJECT_DIR$/pom.xml" />
+      </list>
+    </option>
+  </component>
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_1_8" project-jdk-name="1.8" project-jdk-type="JavaSDK">
+    <output url="file://$PROJECT_DIR$/out" />
+  </component>
+</project>
\ No newline at end of file
diff --git a/.idea/uiDesigner.xml b/.idea/uiDesigner.xml
new file mode 100644
index 0000000..e96534f
--- /dev/null
+++ b/.idea/uiDesigner.xml
@@ -0,0 +1,124 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="Palette2">
+    <group name="Swing">
+      <item class="com.intellij.uiDesigner.HSpacer" tooltip-text="Horizontal Spacer" icon="/com/intellij/uiDesigner/icons/hspacer.png" removable="false" auto-create-binding="false" can-attach-label="false">
+        <default-constraints vsize-policy="1" hsize-policy="6" anchor="0" fill="1" />
+      </item>
+      <item class="com.intellij.uiDesigner.VSpacer" tooltip-text="Vertical Spacer" icon="/com/intellij/uiDesigner/icons/vspacer.png" removable="false" auto-create-binding="false" can-attach-label="false">
+        <default-constraints vsize-policy="6" hsize-policy="1" anchor="0" fill="2" />
+      </item>
+      <item class="javax.swing.JPanel" icon="/com/intellij/uiDesigner/icons/panel.png" removable="false" auto-create-binding="false" can-attach-label="false">
+        <default-constraints vsize-policy="3" hsize-policy="3" anchor="0" fill="3" />
+      </item>
+      <item class="javax.swing.JScrollPane" icon="/com/intellij/uiDesigner/icons/scrollPane.png" removable="false" auto-create-binding="false" can-attach-label="true">
+        <default-constraints vsize-policy="7" hsize-policy="7" anchor="0" fill="3" />
+      </item>
+      <item class="javax.swing.JButton" icon="/com/intellij/uiDesigner/icons/button.png" removable="false" auto-create-binding="true" can-attach-label="false">
+        <default-constraints vsize-policy="0" hsize-policy="3" anchor="0" fill="1" />
+        <initial-values>
+          <property name="text" value="Button" />
+        </initial-values>
+      </item>
+      <item class="javax.swing.JRadioButton" icon="/com/intellij/uiDesigner/icons/radioButton.png" removable="false" auto-create-binding="true" can-attach-label="false">
+        <default-constraints vsize-policy="0" hsize-policy="3" anchor="8" fill="0" />
+        <initial-values>
+          <property name="text" value="RadioButton" />
+        </initial-values>
+      </item>
+      <item class="javax.swing.JCheckBox" icon="/com/intellij/uiDesigner/icons/checkBox.png" removable="false" auto-create-binding="true" can-attach-label="false">
+        <default-constraints vsize-policy="0" hsize-policy="3" anchor="8" fill="0" />
+        <initial-values>
+          <property name="text" value="CheckBox" />
+        </initial-values>
+      </item>
+      <item class="javax.swing.JLabel" icon="/com/intellij/uiDesigner/icons/label.png" removable="false" auto-create-binding="false" can-attach-label="false">
+        <default-constraints vsize-policy="0" hsize-policy="0" anchor="8" fill="0" />
+        <initial-values>
+          <property name="text" value="Label" />
+        </initial-values>
+      </item>
+      <item class="javax.swing.JTextField" icon="/com/intellij/uiDesigner/icons/textField.png" removable="false" auto-create-binding="true" can-attach-label="true">
+        <default-constraints vsize-policy="0" hsize-policy="6" anchor="8" fill="1">
+          <preferred-size width="150" height="-1" />
+        </default-constraints>
+      </item>
+      <item class="javax.swing.JPasswordField" icon="/com/intellij/uiDesigner/icons/passwordField.png" removable="false" auto-create-binding="true" can-attach-label="true">
+        <default-constraints vsize-policy="0" hsize-policy="6" anchor="8" fill="1">
+          <preferred-size width="150" height="-1" />
+        </default-constraints>
+      </item>
+      <item class="javax.swing.JFormattedTextField" icon="/com/intellij/uiDesigner/icons/formattedTextField.png" removable="false" auto-create-binding="true" can-attach-label="true">
+        <default-constraints vsize-policy="0" hsize-policy="6" anchor="8" fill="1">
+          <preferred-size width="150" height="-1" />
+        </default-constraints>
+      </item>
+      <item class="javax.swing.JTextArea" icon="/com/intellij/uiDesigner/icons/textArea.png" removable="false" auto-create-binding="true" can-attach-label="true">
+        <default-constraints vsize-policy="6" hsize-policy="6" anchor="0" fill="3">
+          <preferred-size width="150" height="50" />
+        </default-constraints>
+      </item>
+      <item class="javax.swing.JTextPane" icon="/com/intellij/uiDesigner/icons/textPane.png" removable="false" auto-create-binding="true" can-attach-label="true">
+        <default-constraints vsize-policy="6" hsize-policy="6" anchor="0" fill="3">
+          <preferred-size width="150" height="50" />
+        </default-constraints>
+      </item>
+      <item class="javax.swing.JEditorPane" icon="/com/intellij/uiDesigner/icons/editorPane.png" removable="false" auto-create-binding="true" can-attach-label="true">
+        <default-constraints vsize-policy="6" hsize-policy="6" anchor="0" fill="3">
+          <preferred-size width="150" height="50" />
+        </default-constraints>
+      </item>
+      <item class="javax.swing.JComboBox" icon="/com/intellij/uiDesigner/icons/comboBox.png" removable="false" auto-create-binding="true" can-attach-label="true">
+        <default-constraints vsize-policy="0" hsize-policy="2" anchor="8" fill="1" />
+      </item>
+      <item class="javax.swing.JTable" icon="/com/intellij/uiDesigner/icons/table.png" removable="false" auto-create-binding="true" can-attach-label="false">
+        <default-constraints vsize-policy="6" hsize-policy="6" anchor="0" fill="3">
+          <preferred-size width="150" height="50" />
+        </default-constraints>
+      </item>
+      <item class="javax.swing.JList" icon="/com/intellij/uiDesigner/icons/list.png" removable="false" auto-create-binding="true" can-attach-label="false">
+        <default-constraints vsize-policy="6" hsize-policy="2" anchor="0" fill="3">
+          <preferred-size width="150" height="50" />
+        </default-constraints>
+      </item>
+      <item class="javax.swing.JTree" icon="/com/intellij/uiDesigner/icons/tree.png" removable="false" auto-create-binding="true" can-attach-label="false">
+        <default-constraints vsize-policy="6" hsize-policy="6" anchor="0" fill="3">
+          <preferred-size width="150" height="50" />
+        </default-constraints>
+      </item>
+      <item class="javax.swing.JTabbedPane" icon="/com/intellij/uiDesigner/icons/tabbedPane.png" removable="false" auto-create-binding="true" can-attach-label="false">
+        <default-constraints vsize-policy="3" hsize-policy="3" anchor="0" fill="3">
+          <preferred-size width="200" height="200" />
+        </default-constraints>
+      </item>
+      <item class="javax.swing.JSplitPane" icon="/com/intellij/uiDesigner/icons/splitPane.png" removable="false" auto-create-binding="false" can-attach-label="false">
+        <default-constraints vsize-policy="3" hsize-policy="3" anchor="0" fill="3">
+          <preferred-size width="200" height="200" />
+        </default-constraints>
+      </item>
+      <item class="javax.swing.JSpinner" icon="/com/intellij/uiDesigner/icons/spinner.png" removable="false" auto-create-binding="true" can-attach-label="true">
+        <default-constraints vsize-policy="0" hsize-policy="6" anchor="8" fill="1" />
+      </item>
+      <item class="javax.swing.JSlider" icon="/com/intellij/uiDesigner/icons/slider.png" removable="false" auto-create-binding="true" can-attach-label="false">
+        <default-constraints vsize-policy="0" hsize-policy="6" anchor="8" fill="1" />
+      </item>
+      <item class="javax.swing.JSeparator" icon="/com/intellij/uiDesigner/icons/separator.png" removable="false" auto-create-binding="false" can-attach-label="false">
+        <default-constraints vsize-policy="6" hsize-policy="6" anchor="0" fill="3" />
+      </item>
+      <item class="javax.swing.JProgressBar" icon="/com/intellij/uiDesigner/icons/progressbar.png" removable="false" auto-create-binding="true" can-attach-label="false">
+        <default-constraints vsize-policy="0" hsize-policy="6" anchor="0" fill="1" />
+      </item>
+      <item class="javax.swing.JToolBar" icon="/com/intellij/uiDesigner/icons/toolbar.png" removable="false" auto-create-binding="false" can-attach-label="false">
+        <default-constraints vsize-policy="0" hsize-policy="6" anchor="0" fill="1">
+          <preferred-size width="-1" height="20" />
+        </default-constraints>
+      </item>
+      <item class="javax.swing.JToolBar$Separator" icon="/com/intellij/uiDesigner/icons/toolbarSeparator.png" removable="false" auto-create-binding="false" can-attach-label="false">
+        <default-constraints vsize-policy="0" hsize-policy="0" anchor="0" fill="1" />
+      </item>
+      <item class="javax.swing.JScrollBar" icon="/com/intellij/uiDesigner/icons/scrollbar.png" removable="false" auto-create-binding="true" can-attach-label="false">
+        <default-constraints vsize-policy="6" hsize-policy="0" anchor="0" fill="2" />
+      </item>
+    </group>
+  </component>
+</project>
\ No newline at end of file
diff --git a/.idea/workspace.xml b/.idea/workspace.xml
new file mode 100644
index 0000000..d128cd0
--- /dev/null
+++ b/.idea/workspace.xml
@@ -0,0 +1,286 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ChangeListManager">
+    <list default="true" id="a609a0a0-94e8-451b-a70b-2605da1cae25" name="Default Changelist" comment="" />
+    <ignored path="$PROJECT_DIR$/out/" />
+    <ignored path="$PROJECT_DIR$/target/" />
+    <option name="EXCLUDED_CONVERTED_TO_IGNORED" value="true" />
+    <option name="SHOW_DIALOG" value="false" />
+    <option name="HIGHLIGHT_CONFLICTS" value="true" />
+    <option name="HIGHLIGHT_NON_ACTIVE_CHANGELIST" value="false" />
+    <option name="LAST_RESOLUTION" value="IGNORE" />
+  </component>
+  <component name="FileEditorManager">
+    <leaf>
+      <file pinned="false" current-in-tab="false">
+        <entry file="file://$PROJECT_DIR$/pom.xml">
+          <provider selected="true" editor-type-id="text-editor">
+            <state relative-caret-position="333">
+              <caret line="107" column="36" selection-start-line="107" selection-start-column="36" selection-end-line="107" selection-end-column="36" />
+            </state>
+          </provider>
+        </entry>
+      </file>
+      <file pinned="false" current-in-tab="true">
+        <entry file="file://$PROJECT_DIR$/src/main/java/com/doodream/robustdns/RobustDnsResolver.java">
+          <provider selected="true" editor-type-id="text-editor">
+            <state relative-caret-position="435">
+              <caret line="64" lean-forward="true" selection-start-line="64" selection-end-line="64" />
+              <folding>
+                <element signature="imports" expanded="true" />
+                <element signature="e#2259#2260#0" expanded="true" />
+              </folding>
+            </state>
+          </provider>
+        </entry>
+      </file>
+    </leaf>
+  </component>
+  <component name="FileTemplateManagerImpl">
+    <option name="RECENT_TEMPLATES">
+      <list>
+        <option value="Class" />
+      </list>
+    </option>
+  </component>
+  <component name="IdeDocumentHistory">
+    <option name="CHANGED_PATHS">
+      <list>
+        <option value="$PROJECT_DIR$/pom.xml" />
+        <option value="$PROJECT_DIR$/src/main/java/com/doodream/robustdns/Resolver.java" />
+        <option value="$PROJECT_DIR$/src/main/java/com/doodream/robustdns/RobustDnsResolver.java" />
+      </list>
+    </option>
+  </component>
+  <component name="MavenImportPreferences">
+    <option name="importingSettings">
+      <MavenImportingSettings>
+        <option name="importAutomatically" value="true" />
+      </MavenImportingSettings>
+    </option>
+  </component>
+  <component name="ProjectFrameBounds" extendedState="6">
+    <option name="x" value="1920" />
+    <option name="y" value="-2" />
+    <option name="width" value="1920" />
+    <option name="height" value="1082" />
+  </component>
+  <component name="ProjectView">
+    <navigator proportions="" version="1">
+      <foldersAlwaysOnTop value="true" />
+    </navigator>
+    <panes>
+      <pane id="PackagesPane" />
+      <pane id="ProjectPane">
+        <subPane>
+          <expand>
+            <path>
+              <item name="robustdns" type="b2602c69:ProjectViewProjectNode" />
+              <item name="robustdns" type="462c0819:PsiDirectoryNode" />
+            </path>
+            <path>
+              <item name="robustdns" type="b2602c69:ProjectViewProjectNode" />
+              <item name="robustdns" type="462c0819:PsiDirectoryNode" />
+              <item name="src" type="462c0819:PsiDirectoryNode" />
+            </path>
+            <path>
+              <item name="robustdns" type="b2602c69:ProjectViewProjectNode" />
+              <item name="robustdns" type="462c0819:PsiDirectoryNode" />
+              <item name="src" type="462c0819:PsiDirectoryNode" />
+              <item name="main" type="462c0819:PsiDirectoryNode" />
+            </path>
+          </expand>
+          <select />
+        </subPane>
+      </pane>
+      <pane id="Scope" />
+    </panes>
+  </component>
+  <component name="PropertiesComponent">
+    <property name="WebServerToolWindowFactoryState" value="false" />
+    <property name="aspect.path.notification.shown" value="true" />
+    <property name="com.android.tools.idea.instantapp.provision.ProvisionBeforeRunTaskProvider.myTimeStamp" value="1556258389616" />
+    <property name="nodejs_interpreter_path.stuck_in_default_project" value="undefined stuck path" />
+    <property name="nodejs_npm_path_reset_for_default_project" value="true" />
+    <property name="project.structure.last.edited" value="Modules" />
+    <property name="project.structure.proportion" value="0.0" />
+    <property name="project.structure.side.proportion" value="0.0" />
+  </component>
+  <component name="RunDashboard">
+    <option name="ruleStates">
+      <list>
+        <RuleState>
+          <option name="name" value="ConfigurationTypeDashboardGroupingRule" />
+        </RuleState>
+        <RuleState>
+          <option name="name" value="StatusDashboardGroupingRule" />
+        </RuleState>
+      </list>
+    </option>
+  </component>
+  <component name="SvnConfiguration">
+    <configuration />
+  </component>
+  <component name="TaskManager">
+    <task active="true" id="Default" summary="Default task">
+      <changelist id="a609a0a0-94e8-451b-a70b-2605da1cae25" name="Default Changelist" comment="" />
+      <created>1556256144233</created>
+      <option name="number" value="Default" />
+      <option name="presentableId" value="Default" />
+      <updated>1556256144233</updated>
+      <workItem from="1556256147212" duration="2226000" />
+    </task>
+    <servers />
+  </component>
+  <component name="TimeTrackingManager">
+    <option name="totallyTimeSpent" value="2226000" />
+  </component>
+  <component name="ToolWindowManager">
+    <frame x="1920" y="-2" width="1920" height="1082" extended-state="6" />
+    <editor active="true" />
+    <layout>
+      <window_info id="Designer" />
+      <window_info id="Image Layers" />
+      <window_info id="UI Designer" />
+      <window_info id="Favorites" side_tool="true" />
+      <window_info id="Capture Tool" />
+      <window_info content_ui="combo" id="Project" order="0" weight="0.2497332" />
+      <window_info id="Structure" order="1" side_tool="true" weight="0.25" />
+      <window_info anchor="bottom" id="Terminal" visible="true" weight="0.32984293" />
+      <window_info anchor="bottom" id="Event Log" side_tool="true" />
+      <window_info anchor="bottom" id="Database Changes" />
+      <window_info anchor="bottom" id="Version Control" />
+      <window_info anchor="bottom" id="Docker" show_stripe_button="false" />
+      <window_info anchor="bottom" id="Message" order="0" />
+      <window_info anchor="bottom" id="Find" order="1" />
+      <window_info anchor="bottom" id="Run" order="2" />
+      <window_info anchor="bottom" id="Debug" order="3" weight="0.4" />
+      <window_info anchor="bottom" id="Cvs" order="4" weight="0.25" />
+      <window_info anchor="bottom" id="Inspection" order="5" weight="0.4" />
+      <window_info anchor="bottom" id="TODO" order="6" />
+      <window_info anchor="right" id="Maven" />
+      <window_info anchor="right" id="PlantUML" />
+      <window_info anchor="right" id="Palette" />
+      <window_info anchor="right" id="Capture Analysis" />
+      <window_info anchor="right" id="Cargo" />
+      <window_info anchor="right" id="SciView" />
+      <window_info anchor="right" id="Database" />
+      <window_info anchor="right" id="Palette&#9;" />
+      <window_info anchor="right" id="Theme Preview" />
+      <window_info anchor="right" id="Commander" internal_type="SLIDING" order="0" type="SLIDING" weight="0.4" />
+      <window_info anchor="right" id="Ant Build" order="1" weight="0.25" />
+      <window_info anchor="right" content_ui="combo" id="Hierarchy" order="2" weight="0.25" />
+    </layout>
+  </component>
+  <component name="TypeScriptGeneratedFilesManager">
+    <option name="version" value="1" />
+  </component>
+  <component name="editorHistoryManager">
+    <entry file="file://$PROJECT_DIR$/pom.xml">
+      <provider selected="true" editor-type-id="text-editor">
+        <state relative-caret-position="333">
+          <caret line="107" column="36" selection-start-line="107" selection-start-column="36" selection-end-line="107" selection-end-column="36" />
+        </state>
+      </provider>
+    </entry>
+    <entry file="jar:///usr/lib/jvm/java-8-openjdk-amd64/jre/lib/rt.jar!/java/net/InetSocketAddress.class">
+      <provider selected="true" editor-type-id="text-editor">
+        <state relative-caret-position="204">
+          <caret line="40" column="11" selection-start-line="40" selection-start-column="11" selection-end-line="40" selection-end-column="11" />
+          <folding>
+            <element signature="e#1278#1279#0" expanded="true" />
+            <element signature="e#1335#1336#0" expanded="true" />
+          </folding>
+        </state>
+      </provider>
+    </entry>
+    <entry file="file://$PROJECT_DIR$/src/main/java/com/doodream/robustdns/RobustDnsResolver.java">
+      <provider selected="true" editor-type-id="text-editor">
+        <state relative-caret-position="435">
+          <caret line="64" lean-forward="true" selection-start-line="64" selection-end-line="64" />
+          <folding>
+            <element signature="imports" expanded="true" />
+            <element signature="e#2259#2260#0" expanded="true" />
+          </folding>
+        </state>
+      </provider>
+    </entry>
+  </component>
+  <component name="masterDetails">
+    <states>
+      <state key="ArtifactsStructureConfigurable.UI">
+        <settings>
+          <artifact-editor />
+          <splitter-proportions>
+            <option name="proportions">
+              <list>
+                <option value="0.2" />
+              </list>
+            </option>
+          </splitter-proportions>
+        </settings>
+      </state>
+      <state key="FacetStructureConfigurable.UI">
+        <settings>
+          <last-edited>No facets are configured</last-edited>
+          <splitter-proportions>
+            <option name="proportions">
+              <list>
+                <option value="0.2" />
+              </list>
+            </option>
+          </splitter-proportions>
+        </settings>
+      </state>
+      <state key="GlobalLibrariesConfigurable.UI">
+        <settings>
+          <last-edited>Python 2.7 interpreter library</last-edited>
+          <splitter-proportions>
+            <option name="proportions">
+              <list>
+                <option value="0.2" />
+              </list>
+            </option>
+          </splitter-proportions>
+        </settings>
+      </state>
+      <state key="JdkListConfigurable.UI">
+        <settings>
+          <last-edited>1.8</last-edited>
+          <splitter-proportions>
+            <option name="proportions">
+              <list>
+                <option value="0.2" />
+              </list>
+            </option>
+          </splitter-proportions>
+        </settings>
+      </state>
+      <state key="ModuleStructureConfigurable.UI">
+        <settings>
+          <last-edited>robustdns</last-edited>
+          <splitter-proportions>
+            <option name="proportions">
+              <list>
+                <option value="0.2" />
+                <option value="0.6" />
+              </list>
+            </option>
+          </splitter-proportions>
+        </settings>
+      </state>
+      <state key="ProjectLibrariesConfigurable.UI">
+        <settings>
+          <last-edited>Maven: com.google.code.gson:gson:2.8.5</last-edited>
+          <splitter-proportions>
+            <option name="proportions">
+              <list>
+                <option value="0.2" />
+              </list>
+            </option>
+          </splitter-proportions>
+        </settings>
+      </state>
+    </states>
+  </component>
+</project>
\ No newline at end of file
diff --git a/pom.xml b/pom.xml
new file mode 100644
index 0000000..6fa8184
--- /dev/null
+++ b/pom.xml
@@ -0,0 +1,123 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>com.doodream</groupId>
+    <artifactId>robust-dns</artifactId>
+    <version>1.0.0-SNAPSHOT</version>
+    <packaging>jar</packaging>
+    <properties>
+        <rxjava_version>2.1.12</rxjava_version>
+        <lombok_version>1.16.6</lombok_version>
+        <slf4j_version>1.7.25</slf4j_version>
+        <gson_version>2.8.5</gson_version>
+        <maven.repository>maven_repository</maven.repository>
+    </properties>
+
+    <licenses>
+        <license>
+            <name>Apache License, Version 2.0</name>
+            <url>http://www.apache.org/licenses/LICENSE-2.0.txt</url>
+            <distribution>repo</distribution>
+        </license>
+    </licenses>
+
+    <build>
+        <extensions>
+            <extension>
+                <groupId>ar.com.synergian</groupId>
+                <artifactId>wagon-git</artifactId>
+                <version>0.3.1</version>
+            </extension>
+        </extensions>
+        <resources>
+            <resource>
+                <directory>src/main/resources</directory>
+                <filtering>true</filtering>
+            </resource>
+            <resource>
+                <directory>src/test/resources</directory>
+                <filtering>true</filtering>
+            </resource>
+        </resources>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-surefire-plugin</artifactId>
+                <version>2.21.0</version>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-resources-plugin</artifactId>
+                <version>2.6</version>
+            </plugin>
+            <plugin>
+                <artifactId>maven-deploy-plugin</artifactId>
+                <version>2.8.1</version>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-assembly-plugin</artifactId>
+                <executions>
+                    <execution>
+                        <phase>package</phase>
+                        <goals>
+                            <goal>single</goal>
+                        </goals>
+                        <configuration>
+                            <descriptorRefs>
+                                <descriptorRef>jar-with-dependencies</descriptorRef>
+                            </descriptorRefs>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>3.6.1</version>
+                <configuration>
+                    <source>1.8</source>
+                    <target>1.8</target>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+    <dependencies>
+        <dependency>
+            <groupId>io.reactivex.rxjava2</groupId>
+            <artifactId>rxjava</artifactId>
+            <version>${rxjava_version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.projectlombok</groupId>
+            <artifactId>lombok</artifactId>
+            <version>${lombok_version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.slf4j</groupId>
+            <artifactId>slf4j-api</artifactId>
+            <version>${slf4j_version}</version>
+        </dependency>
+
+        <dependency>
+            <groupId>dnsjava</groupId>
+            <artifactId>dnsjava</artifactId>
+            <version>2.1.8</version>
+        </dependency>
+        <dependency>
+            <groupId>com.google.code.gson</groupId>
+            <artifactId>gson</artifactId>
+            <version>${gson_version}</version>
+        </dependency>
+
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>4.8.1</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+</project>
\ No newline at end of file
diff --git a/robustdns.iml b/robustdns.iml
new file mode 100644
index 0000000..78b2cc5
--- /dev/null
+++ b/robustdns.iml
@@ -0,0 +1,2 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4" />
\ No newline at end of file
diff --git a/src/main/java/com/doodream/robustdns/RobustDnsResolver.java b/src/main/java/com/doodream/robustdns/RobustDnsResolver.java
new file mode 100644
index 0000000..09701d4
--- /dev/null
+++ b/src/main/java/com/doodream/robustdns/RobustDnsResolver.java
@@ -0,0 +1,67 @@
+package com.doodream.robustdns;
+
+import io.reactivex.Observable;
+import io.reactivex.Single;
+import org.xbill.DNS.*;
+
+import java.io.IOException;
+import java.net.UnknownHostException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Locale;
+
+public class RobustDnsResolver {
+
+    private static final String[] CREDIBLE_DNS_ADDRESS = {
+            "8.8.8.8",
+            "8.8.4.4",
+            "1.1.1.1",
+            "205.251.198.30"
+    };
+
+    private final ExtendedResolver resolver;
+
+
+    public RobustDnsResolver(String ...dnsUrls) throws UnknownHostException {
+        List<String> urls = new ArrayList<>();
+        if(dnsUrls != null && dnsUrls.length > 0) {
+            urls.addAll(Arrays.asList(dnsUrls));
+        }
+        urls.addAll(Arrays.asList(CREDIBLE_DNS_ADDRESS));
+        String[] allDnsUrls = urls.toArray(new String[0]);
+        resolver = new ExtendedResolver(Observable.fromArray(allDnsUrls)
+                .map(dnsAddress -> new SimpleResolver(dnsAddress))
+                .toList()
+                .blockingGet()
+                .toArray(new Resolver[0]));
+    }
+
+    public RobustDnsResolver() throws UnknownHostException {
+        this(new String[0]);
+    }
+
+    public Single<String> resolve(String name) throws IOException {
+        return Single.create(emitter -> {
+            final Record question = Record.newRecord(Name.concatenate(Name.fromString(name), Name.root), Type.A, DClass.IN, TTL.MAX_VALUE);
+            final Message query = Message.newQuery(question);
+            resolver.sendAsync(query, new ResolverListener() {
+                @Override
+                public void receiveMessage(Object o, Message message) {
+                    Record[] records = message.getSectionArray(Section.ANSWER);
+                    if(records != null || records.length > 0) {
+                        emitter.onSuccess(records[0].rdataToString());
+                    } else {
+                        emitter.onError(new UnknownHostException(String.format(Locale.ENGLISH, "%s not found", name)));
+                    }
+                }
+
+                @Override
+                public void handleException(Object o, Exception e) {
+                    emitter.onError(e);
+                }
+            });
+        });
+
+    }
+}