[JAVA]sslCaCert InputStream is getting exhausted when loading SSLCerts in ApiClient.java/apiclient.mustache

Description

in ApiClient.java/apiclient.mustache applySslSettings() is called when ever we set sslCerts||verifySSL||keyManagers.
if we form ApiClient object like following

 ApiClient client=  new ApiClient()
		 .setBasePath("https://192.168.42.250:8443")
		 .setSslCaCert(new ByteArrayInputStream(caSSLcert))
		 .setKeyManagers(SSLUtils.keyManagers(clientcert, clientKey, "RSA", "", null, null))
		 .setVerifyingSsl(true);

applySslSettings() will be called multiple times, but will fail(at setkeyManagers()) saying

Exception in thread "main" java.lang.IllegalArgumentException: expected non-empty set of trusted certificates
	at io.kubernetes.client.ApiClient.applySslSettings(ApiClient.java:1130)
	at io.kubernetes.client.ApiClient.setKeyManagers(ApiClient.java:219)
	at io.kubernetes.client.examples.Example.main(Example.java:57)

sslCaCert will get exhausted after setSslCert() call and when setKeyManagers() is called it fails.

we have observed this issue in kubernetes java client:
we have ClientBuilder class which Builds APiClient.

Swagger-codegen version

i believe its 2.3.0 ( https://github.com/kubernetes-client/java/blob/master/kubernetes/.swagger-codegen/VERSION)

Swagger declaration file content or url

https://raw.githubusercontent.com/kubernetes-client/java/master/kubernetes/swagger.json

Related issues/PRs

This has been observed in https://github.com/kubernetes-client/java/issues/199 by @brendandburns

Suggest a fix/enhancement

In apiclient.mustache
either make a clone of sslCaCert and pass the clone to generateCertificates(sslCaCert);

 private void applySslSettings() {
.
.
.
else if (sslCaCert != null) {
byte[] targetArray = null ;
        try {
          targetArray = new byte[sslCaCert.available()];
          sslCaCert.read(targetArray);
        }
        catch(Exception e) {
        }
        sslCaCert = new ByteArrayInputStream(targetArray);
        char[] password = null; // Any password will work.
        InputStream sslCaCertCopy =  new ByteArrayInputStream(targetArray);
        CertificateFactory certificateFactory = CertificateFactory.getInstance("X.509");
        Collection<? extends Certificate> certificates = certificateFactory.generateCertificates(sslCaCertCopy);
.
.
.

or instead of using InputStream, can use byte[] in setters for sslcaCerts and just convert to InputStream before passing it to certificateFactory.generateCertificates()

Start in apiclient.mustache and the generated ApiClient.java, focusing on applySslSettings() and the setSslCaCert(), setKeyManagers(), and setVerifyingSsl() calls. Reproduce the chained setter example with the Java client and trace how sslCaCert is consumed. Done means applying SSL settings repeatedly no longer exhausts the certificate stream or raises the empty trusted-certificates error.