Add option to select http client

The plugin depends on network library yavijava
https://github.com/jenkinsci/vsphere-cloud-plugin/blob/master/pom.xml#L95-L96
The yavijava supports two types of http clients:
`CloseableHttpClient`
`HttpURLConnection` - is default
The HttpURLConnection client's behaviour can be impacted by system-wide
cookie handler CookieManager:
https://docs.oracle.com/javase/8/docs/api/java/net/CookieManager.html
The major problem is that the CookieManager overlaps logic provided by
HttpURLConnection to setup http header `Cookie`. Global CookieManager
know nothing about logic of vsphere-cloud-plugin and fill all http
headers with stored cookies, as result vsphere center rejects login
requests with error:
```
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:soapenc="http://schemas.xmlsoap.org/soap/encoding/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
	<soapenv:Body>
		<soapenv:Fault>
			<faultcode>ServerFaultCode</faultcode>
			<faultstring>Cannot complete login due to an incorrect user name or password.</faultstring>
			<detail>
				<InvalidLoginFault xmlns="urn:vim25" xsi:type="InvalidLogin">
					<faultMessage>
						<key>vim.fault.InvalidLoginWithReason</key>
						<arg>
							<key>1</key>
							<value xsi:type="xsd:string">vim.fault.InvalidLoginReasonRegisterFailed</value>
						</arg>
						<message>Login failed because the session could not be re-registered.</message>
					</faultMessage>
				</InvalidLoginFault>
			</detail>
		</soapenv:Fault>
	</soapenv:Body>
</soapenv:Envelope>
```

The vsphere-cloud-plugin does not use CookieManager, but there is no
guarantee that other plugins avoid it. Example:
https://github.com/jenkinsci/parameterized-remote-trigger-plugin/blob/master/src/main/java/org/jenkinsci/plugins/ParameterizedRemoteTrigger/RemoteBuildConfiguration.java#L158-L159

As workaroud we can switch to CloseableHttpClient http client.

Issue in Jira:
https://issues.jenkins.io/browse/JENKINS-69999

Author: lifemanship

src/main/java/org/jenkinsci/plugins/vSphereCloud.java

@@ -172,7 +172,7 @@ public vSphereCloud(VSphereConnectionConfig vsConnectionConfig, String vsDescrip
 
     public Object readResolve() throws IOException {
         if (vsConnectionConfig == null) {
-            vsConnectionConfig = new VSphereConnectionConfig(vsHost, null);
+            vsConnectionConfig = new VSphereConnectionConfig(vsHost, null, null);
         }
         if (this.templates != null) {
             for (vSphereCloudSlaveTemplate template : templates) {
@@ -630,9 +630,11 @@ public static List<vSphereCloud> findAllVsphereClouds(String jobName) {
             }
         }
 
-        for (Cloud cloud : Jenkins.getInstance().clouds) {
-            if (cloud instanceof vSphereCloud) {
-                vSphereClouds.add((vSphereCloud) cloud);
+        if (Jenkins.getInstance() != null) {
+            for (Cloud cloud : Jenkins.getInstance().clouds) {
+                if (cloud instanceof vSphereCloud) {
+                    vSphereClouds.add((vSphereCloud) cloud);
+                }
             }
         }
         return vSphereClouds;

src/main/java/org/jenkinsci/plugins/vsphere/VSphereConnectionConfig.java

@@ -28,6 +28,8 @@
 import com.cloudbees.plugins.credentials.common.StandardUsernamePasswordCredentials;
 import com.cloudbees.plugins.credentials.domains.DomainRequirement;
 import com.cloudbees.plugins.credentials.domains.HostnameRequirement;
+import com.vmware.vim25.ws.ApacheHttpClient;
+import com.vmware.vim25.ws.WSClient;
 import hudson.Extension;
 import hudson.Util;
 import hudson.model.AbstractDescribableImpl;
@@ -37,11 +39,14 @@
 import hudson.util.ListBoxModel;
 import hudson.util.Secret;
 import java.util.Collections;
+import java.util.List;
+
 import edu.umd.cs.findbugs.annotations.CheckForNull;
 import edu.umd.cs.findbugs.annotations.NonNull;
 import jenkins.model.Jenkins;
 
 import org.apache.commons.lang.StringUtils;
+import org.jenkinsci.plugins.vSphereCloud;
 import org.jenkinsci.plugins.vsphere.tools.VSphere;
 import org.kohsuke.stapler.AncestorInPath;
 import org.kohsuke.stapler.DataBoundConstructor;
@@ -58,16 +63,71 @@ public class VSphereConnectionConfig extends AbstractDescribableImpl<VSphereConn
     private final @CheckForNull String vsHost;
     private /*final*/ boolean allowUntrustedCertificate;
     private final @CheckForNull String credentialsId;
-    
+
+    private enum HttpClientClassName {
+        ApacheHttpClientClass("ApacheHttpClient"),
+        WSClientClass("WSClient");
+
+        public final String name;
+
+        private HttpClientClassName(String name) {
+            this.name = name;
+        }
+    }
+
+    private static Class<?> httpClientNameToClass(String httpClientClassName) {
+        if (httpClientClassName.equals(HttpClientClassName.ApacheHttpClientClass.name)) {
+            return ApacheHttpClient.class;
+        }
+        return WSClient.class;
+    }
+
+    private static String httpClientClassToName(Class<?> httpClientClass) {
+        if (httpClientClass == ApacheHttpClient.class) {
+            return HttpClientClassName.ApacheHttpClientClass.name;
+        }
+        return HttpClientClassName.WSClientClass.name;
+    }
+
+    private String httpClientClassName;
+
+    private static Class<?> httpClientClass;
+
+    public static Class<?> setupGlobalHttpClientClass() {
+        if (VSphereConnectionConfig.httpClientClass == null) {
+            VSphereConnectionConfig.httpClientClass = WSClient.class;
+            List<vSphereCloud> clouds = vSphereCloud.findAllVsphereClouds(null);
+            if (clouds.size() > 0) {
+                VSphereConnectionConfig.httpClientClass
+                        = httpClientNameToClass(clouds.get(0).getVsConnectionConfig().httpClientClassName);
+            }
+        }
+        return VSphereConnectionConfig.httpClientClass;
+    }
+
+    public static String getHttpClientClassName() {
+        return httpClientClassToName(setupGlobalHttpClientClass());
+    }
+
+    @DataBoundSetter
+    public void setHttpClientClassName(String httpClientClassName) {
+        this.httpClientClassName = (httpClientClassName == null) ? getHttpClientClassName() : httpClientClassName;
+        for (vSphereCloud cloud : vSphereCloud.findAllVsphereClouds(null)) {
+            cloud.getVsConnectionConfig().httpClientClassName = this.httpClientClassName;
+        }
+        VSphereConnectionConfig.httpClientClass = httpClientNameToClass(this.httpClientClassName);
+    }
+
     @DataBoundConstructor
-    public VSphereConnectionConfig(String vsHost, String credentialsId) {
+    public VSphereConnectionConfig(String vsHost, String credentialsId, String httpClientClassName) {
         this.vsHost = vsHost;
         this.credentialsId = credentialsId;
+        setHttpClientClassName(httpClientClassName);
     }
 
     /** Full constructor for internal use, initializes all fields */
     public VSphereConnectionConfig(String vsHost, boolean allowUntrustedCertificate, String credentialsId) {
-        this(vsHost, credentialsId);
+        this(vsHost, credentialsId, null);
         setAllowUntrustedCertificate(allowUntrustedCertificate);
     }
 
@@ -119,6 +179,18 @@ public String getDisplayName() {
             return "N/A";
         }
 
+        public ListBoxModel doFillHttpClientClassNameItems(@AncestorInPath AbstractFolder<?> containingFolderOrNull) {
+            throwUnlessUserHasPermissionToConfigureCloud(containingFolderOrNull);
+
+            ListBoxModel items = new ListBoxModel(new ListBoxModel.Option("Use HttpURLConnection to connect to the vSphere cloud",
+                    VSphereConnectionConfig.HttpClientClassName.WSClientClass.name,
+                    VSphereConnectionConfig.HttpClientClassName.WSClientClass.name.equals(getHttpClientClassName())),
+                    new ListBoxModel.Option("Use CloseableHttpClient to connect to the vSphere cloud",
+                            VSphereConnectionConfig.HttpClientClassName.ApacheHttpClientClass.name,
+                            VSphereConnectionConfig.HttpClientClassName.ApacheHttpClientClass.name.equals(getHttpClientClassName())));
+            return items;
+        }
+
         public FormValidation doCheckVsHost(@QueryParameter String value) {
             if (value!=null && value.length() != 0) {
                 if (!value.startsWith("https://")) {

src/main/java/org/jenkinsci/plugins/vsphere/tools/VSphere.java

@@ -24,6 +24,7 @@
 import java.util.logging.Logger;
 import java.util.logging.Level;
 
+import com.vmware.vim25.ws.ClientCreator;
 import edu.umd.cs.findbugs.annotations.CheckForNull;
 import edu.umd.cs.findbugs.annotations.NonNull;
 
@@ -71,6 +72,7 @@ public class VSphere {
 
     private VSphere(@NonNull String url, boolean ignoreCert, @NonNull String user, @CheckForNull String pw) throws VSphereException {
         try {
+            ClientCreator.clientClass = VSphereConnectionConfig.setupGlobalHttpClientClass();
             this.url = new URL(url);
             final ServiceInstance serviceInstance = new ServiceInstance(this.url, user, pw, ignoreCert);
             final ServerConnection serverConnection = serviceInstance.getServerConnection();

src/main/resources/org/jenkinsci/plugins/vsphere/VSphereConnectionConfig/config.groovy

@@ -7,6 +7,10 @@ f.entry(title:_("vSphere Host"), field:"vsHost") {
     f.textbox()
 }
 
+f.entry(title:_("Change Http Client"), field:"httpClientClassName") {
+    f.select()
+}
+
 f.entry(title:_("Disable SSL Check"), field:"allowUntrustedCertificate") {
     f.checkbox()
 }

src/main/resources/org/jenkinsci/plugins/vsphere/VSphereConnectionConfig/help-httpClientClassName.html

@@ -0,0 +1,8 @@
+<div>
+The <b>vSphere Cloud</b> plugin depends on
+<a href="https://github.com/yavijava/yavijava">yavijava</a>
+library, which supports two types of http clients:
+<a href="https://github.com/yavijava/yavijava/blob/gradle/src/main/java/com/vmware/vim25/ws/ApacheHttpClient.java">CloseableHttpClient</a>
+and
+<a href="https://github.com/yavijava/yavijava/blob/gradle/src/main/java/com/vmware/vim25/ws/WSClient.java">HttpURLConnection</a>
+</div>

src/test/resources/org/jenkinsci/plugins/vsphere/tools/expected_output.yml

@@ -30,5 +30,6 @@
       useSnapshot: true
       waitForVMTools: true
     vsConnectionConfig:
+      httpClientClassName: "WSClient"
       vsHost: "https://company-vsphere"
     vsDescription: "Company vSphere"