DropwizardHealthChecks.java

    @Override
    protected void registerHealthChecks(@Nonnull Environment environment)
    {
        super.registerHealthChecks(environment);

        environment.healthChecks().register("healthy", new HealthCheck()
        {
            @Override
            protected Result check()
            {
                return Result.healthy();
            }
        });
        environment.healthChecks().register("unhealthy", new HealthCheck()
        {
            @Override
            protected Result check()
            {
                return Result.unhealthy("I am unhealthy");
            }
        });
        environment.healthChecks().register("throwing", new HealthCheck()
        {
            @Override
            protected Result check()
            {
                throw new RuntimeException("I am unhealthy");
            }
        });
    }

DropwizardHealthChecks.json

{
  "deadlocks": {
    "healthy": true,
    "duration": 10,
    "timestamp": "2023-11-09T10:50:37.643-05:00"
  },
  "healthy": {
    "healthy": true,
    "duration": 0,
    "timestamp": "2023-11-09T10:50:37.631-05:00"
  },
  "unhealthy": {
    "healthy": false,
    "message": "I am unhealthy",
    "duration": 0,
    "timestamp": "2023-11-09T10:50:37.631-05:00"
  },
  "throwing": {
    "healthy": false,
    "message": "I am unhealthy",
    "error": {
      "type": "java.lang.RuntimeException",
      "message": "I am unhealthy",
      "stack": [
        "Application$3.check(Application.java:123)",
        "com.codahale.metrics.health.HealthCheck.execute(HealthCheck.java:374)",
        "com.codahale.metrics.health.HealthCheckRegistry.runHealthChecks(HealthCheckRegistry.java:184)",
        "com.codahale.metrics.servlets.HealthCheckServlet.runHealthChecks(HealthCheckServlet.java:177)",
        "com.codahale.metrics.servlets.HealthCheckServlet.doGet(HealthCheckServlet.java:146)",
        "javax.servlet.http.HttpServlet.service(HttpServlet.java:687)",
        "javax.servlet.http.HttpServlet.service(HttpServlet.java:790)",
        "com.codahale.metrics.servlets.AdminServlet.service(AdminServlet.java:153)",
        "javax.servlet.http.HttpServlet.service(HttpServlet.java:790)",
        "org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:799)",
        "org.eclipse.jetty.servlet.ServletHandler$ChainEnd.doFilter(ServletHandler.java:1656)",
        "io.dropwizard.jersey.filter.AllowedMethodsFilter.handle(AllowedMethodsFilter.java:47)",
        "io.dropwizard.jersey.filter.AllowedMethodsFilter.doFilter(AllowedMethodsFilter.java:41)",
        "org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:193)",
        "org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1626)",
        "org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:552)",
        "org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143)",
        "org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:560)",
        "org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:127)",
        "org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:235)",
        "org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1440)",
        "org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:188)",
        "org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:505)",
        "org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:186)",
        "org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1355)",
        "org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)",
        "io.dropwizard.jetty.RoutingHandler.handle(RoutingHandler.java:52)",
        "org.eclipse.jetty.server.handler.gzip.GzipHandler.handle(GzipHandler.java:772)",
        "io.dropwizard.jetty.ZipExceptionHandlingGzipHandler.handle(ZipExceptionHandlingGzipHandler.java:26)",
        "org.eclipse.jetty.server.handler.RequestLogHandler.handle(RequestLogHandler.java:54)",
        "org.eclipse.jetty.server.handler.StatisticsHandler.handle(StatisticsHandler.java:181)",
        "org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:127)",
        "org.eclipse.jetty.server.Server.handle(Server.java:516)",
        "org.eclipse.jetty.server.HttpChannel.lambda$handle$1(HttpChannel.java:487)",
        "org.eclipse.jetty.server.HttpChannel.dispatch(HttpChannel.java:732)",
        "org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:479)",
        "org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:277)",
        "org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:311)",
        "org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:105)",
        "org.eclipse.jetty.io.ChannelEndPoint$1.run(ChannelEndPoint.java:104)",
        "org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:338)",
        "org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:315)",
        "org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:173)",
        "org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:131)",
        "org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:409)",
        "org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:883)",
        "org.eclipse.jetty.util.thread.QueuedThreadPool$Runner.run(QueuedThreadPool.java:1034)",
        "java.base/java.lang.Thread.run(Thread.java:1583)"
      ]
    },
    "duration": 0,
    "timestamp": "2023-11-09T10:50:37.631-05:00"
  }
}

DropwizardHealthChecks.sh

❯ curl -I -H "Accept: application/json" http://localhost:8081/healthcheck\?pretty\=true
HTTP/1.1 500 Server Error
Date: Thu, 09 Nov 2023 15:52:45 GMT
Content-Type: application/json
Cache-Control: must-revalidate,no-cache,no-store
Content-Length: 4804