Add support for java 1.8

[Avinash-Kamath]

HTTP Client Update:

• net/HttpClient was added in Java 11 removed the dependency
• Replaced the built-in HttpClient with CloseableHttpClient from Apache HttpComponents

URL Encoding:

• encoding was added in Java 10
• Wrapped URL encoding in a try-catch block to handle UnsupportedEncodingException and updated method calls to use StandardCharsets.UTF_8.name() for encoding.

Maven Configuration:

• Downgraded the Java version from 11 to 1.8 in the pom.xml file.

Change all var Keyword (only in tests)