To prevent NPE use pool name for metrics if JDBC URL is not set.

[john9x]

Fix NPE

java.lang.NullPointerException: Cannot invoke "String.toLowerCase()" because "url" is null
        at org.apache.skywalking.apm.plugin.jdbc.connectionurl.parser.URLParser.parser(URLParser.java:47)
        at org.apache.skywalking.apm.plugin.hikaricp.PoolingSealInterceptor.afterMethod(PoolingSealInterceptor.java:52)
        at org.apache.skywalking.apm.agent.core.plugin.interceptor.enhance.InstMethodsInter.intercept(InstMethodsInter.java:110)
        at com.zaxxer.hikari.HikariDataSource.seal(HikariDataSource.java)
        at com.zaxxer.hikari.HikariDataSource.$sw$original$getConnection$08spks0(HikariDataSource.java:112)
        at com.zaxxer.hikari.HikariDataSource.$sw$original$getConnection$08spks0$accessor$$sw$6kb3bn3(HikariDataSource.java)
        at com.zaxxer.hikari.HikariDataSource$$sw$auxiliary$93993q0.call(Unknown Source)
        at org.apache.skywalking.apm.agent.core.plugin.interceptor.enhance.InstMethodsInter.intercept(InstMethodsInter.java:95)

The pool can be configured with data source options but not JDBC URL so in this case we can use pool name for metrics.

• Add a unit test to verify that the fix works.
• Explain briefly why the bug exists and how to fix it.

• If this pull request closes/resolves/fixes an existing issue, replace the issue number. Closes #.
• Update the CHANGES log.

[wu-sheng]

Please provide the demo codes to represent two ways of using.
And changes.md should be updated. Please follow PR template.

[john9x]

Please provide the demo codes to represent two ways of using.

@wu-sheng How should I do this?

https://github.com/brettwooldridge/HikariCP/?tab=readme-ov-file#rocket-initialization
HikariCP pool can be configured using JDBC URL:

HikariConfig config = new HikariConfig();
config.setJdbcUrl("jdbc:mysql://localhost:3306/simpsons");

or using data source properties

Properties props = new Properties();
props.setProperty("dataSourceClassName", "org.postgresql.ds.PGSimpleDataSource");
props.setProperty("dataSource.serverName", "localhost");
...
HikariConfig config = new HikariConfig(props);
HikariDataSource ds = new HikariDataSource(config)