When it is using trusted certificate in JAVA, it needs to be stored in JAVA key store.
JAVA default key store is %JAVA_HOME/jre/lib/security/cacerts
Using following command you can create a specific key store.
keytool -keystore keystore_name -storepass changeit -file \export\home\root.cer -import -alias alias_name -trustcacerts
Then use the following JAVA code to use the created key store.
System.setProperty("javax.net.ssl.trustStore", "./keystore_name ");
System.setProperty("javax.net.ssl.trustStorePassword", "changeit");
System.setProperty("javax.net.ssl.trustStoreType", "JKS");