org.apache.solr.client.solrj.impl.HttpSolrClient$RemoteSolrException: Error from server at http://localhost:8983/solr

This issue happens due to below reasons : 

1. This is mostly a case you did not put your core name in url as  http://localhost:8983/solr/<coreName>  ex: http://localhost:8983/solr/product
2.  Host is incorrect
3.  Host is correct but solr is not running at host
4.  port might be disable
5. Firewall issue

Spring Boot app: Not picking up application.properties?

There are various reason for this issue to occur I'm showing what I had come across.

For me it was due to packaging as pom

I had something in my pom.xml as below 

    <packaging>pom</packaging>

So if you have similar thing, then :

 1. Remove it for spring-boot App. 

 2. Delete target folder or mvn clean. 

 3. then mvn install.

 4. Watch your property under target/classes/application.properties file.