8291512: Snippetize modules API examples

Reviewed-by: darcy

src/java.base/share/classes/java/lang/ModuleLayer.java

@@ -122,26 +122,22 @@ import sun.security.util.SecurityConstants;
  * in this class causes a {@link NullPointerException NullPointerException} to
  * be thrown. </p>
  *
- * <h2> Example usage: </h2>
+ * <h2> Example </h2>
  *
  * <p> This example creates a configuration by resolving a module named
  * "{@code myapp}" with the configuration for the boot layer as the parent. It
  * then creates a new layer with the modules in this configuration. All modules
  * are defined to the same class loader. </p>
  *
- * <pre>{@code
+ * {@snippet :
  *     ModuleFinder finder = ModuleFinder.of(dir1, dir2, dir3);
- *
  *     ModuleLayer parent = ModuleLayer.boot();
- *
- *     Configuration cf = parent.configuration().resolve(finder, ModuleFinder.of(), Set.of("myapp"));
- *
+ *     Configuration cf = parent.configuration()
+ *                              .resolve(finder, ModuleFinder.of(), Set.of("myapp"));
  *     ClassLoader scl = ClassLoader.getSystemClassLoader();
- *
  *     ModuleLayer layer = parent.defineModulesWithOneLoader(cf, scl);
- *
  *     Class<?> c = layer.findLoader("myapp").loadClass("app.Main");
- * }</pre>
+ * }
  *
  * @since 9
  * @see Module#getLayer()

src/java.base/share/classes/java/lang/module/Configuration.java

@@ -83,11 +83,10 @@ import jdk.internal.vm.annotation.Stable;
  * parent configuration. It prints the name of each resolved module and the
  * names of the modules that each module reads. </p>
  *
- * <pre>{@code
+ * {@snippet :
+ *    Path dir1 = ..., dir2 = ..., dir3 = ...;
  *    ModuleFinder finder = ModuleFinder.of(dir1, dir2, dir3);
- *
  *    Configuration parent = ModuleLayer.boot().configuration();
- *
  *    Configuration cf = parent.resolve(finder, ModuleFinder.of(), Set.of("myapp"));
  *    cf.modules().forEach(m -> {
  *        System.out.format("%s -> %s%n",
@@ -96,7 +95,7 @@ import jdk.internal.vm.annotation.Stable;
  *                .map(ResolvedModule::name)
  *                .collect(Collectors.joining(", ")));
  *    });
- * }</pre>
+ * }
  *
  * @since 9
  * @see java.lang.ModuleLayer

src/java.base/share/classes/java/lang/module/ModuleDescriptor.java

@@ -1467,13 +1467,14 @@ public class ModuleDescriptor
      * <cite>The Java Language Specification</cite>. </p>
      *
      * <p> Example usage: </p>
-     * <pre>{@code    ModuleDescriptor descriptor = ModuleDescriptor.newModule("stats.core")
+     * {@snippet :
+     *     ModuleDescriptor descriptor = ModuleDescriptor.newModule("stats.core")
      *         .requires("java.base")
      *         .exports("org.acme.stats.core.clustering")
      *         .exports("org.acme.stats.core.regression")
      *         .packages(Set.of("org.acme.stats.core.internal"))
      *         .build();
-     * }</pre>
+     * }
      *
      * @apiNote A {@code Builder} checks the components and invariants as
      * components are added to the builder. The rationale for this is to detect

src/java.base/share/classes/java/lang/module/ModuleFinder.java

@@ -54,15 +54,12 @@ import jdk.internal.module.SystemModuleFinders;
  *
  * <p> Example usage: </p>
  *
- * <pre>{@code
- *     Path dir1, dir2, dir3;
- *
+ * {@snippet :
+ *     Path dir1 = ..., dir2 = ..., dir3 = ...;
  *     ModuleFinder finder = ModuleFinder.of(dir1, dir2, dir3);
- *
  *     Optional<ModuleReference> omref = finder.find("jdk.foo");
  *     omref.ifPresent(mref -> ... );
- *
- * }</pre>
+ * }
  *
  * <p> The {@link #find(String) find} and {@link #findAll() findAll} methods
  * defined here can fail for several reasons. These include I/O errors, errors