Refactor JSON logging and utility methods

Replaced manual pretty-printing of JSON in OllamaAPI with a new Utils.toJSON method for cleaner logging. Added private constructors to utility classes to prevent instantiation. Updated test and sample code for improved clarity and randomness.

src/test/java/io/github/ollama4j/integrationtests/OllamaAPIIntegrationTest.java

@@ -114,8 +114,7 @@ class OllamaAPIIntegrationTest {
 
     @Test
     @Order(1)
-    void testPing()
-            throws URISyntaxException, IOException, OllamaBaseException, InterruptedException {
+    void testPing() throws OllamaBaseException {
         boolean pingResponse = api.ping();
         assertTrue(pingResponse, "Ping should return true");
     }

src/test/java/io/github/ollama4j/samples/AnnotatedTool.java

@@ -11,6 +11,7 @@ package io.github.ollama4j.samples;
 import io.github.ollama4j.tools.annotations.ToolProperty;
 import io.github.ollama4j.tools.annotations.ToolSpec;
 import java.math.BigDecimal;
+import java.util.Random;
 
 public class AnnotatedTool {
 
@@ -18,7 +19,8 @@ public class AnnotatedTool {
     public String computeImportantConstant(
             @ToolProperty(name = "noOfDigits", desc = "Number of digits that shall be returned")
                     Integer noOfDigits) {
-        return BigDecimal.valueOf((long) (Math.random() * 1000000L), noOfDigits).toString();
+        return BigDecimal.valueOf((long) (new Random().nextLong() * 1000000L), noOfDigits)
+                .toString();
     }
 
     @ToolSpec(desc = "Says hello to a friend!")