Close streams properly.

src/main/java/edu/kit/datamanager/ro_crate/externalproviders/organizationprovider/RorProvider.java

@@ -16,30 +16,31 @@
  */
 public class RorProvider {
 
+  private RorProvider() {}
+
   /**
    * The method that parses a ror entry to a crate entity.
    *
    * @param url the url of the ror entry.
    * @return the created Organization entity.
    */
   public static OrganizationEntity getOrganization(String url) {
-    CloseableHttpClient httpClient = HttpClients.createDefault();
     if (!url.startsWith("https://ror.org/")) {
       throw new IllegalArgumentException("Should provide ror url");
     }
     String newUrl = "https://api.ror.org/organizations/" + url.replaceAll("https://ror.org/", "");
     HttpGet request = new HttpGet(newUrl);
 
-    try {
-      CloseableHttpResponse response = httpClient.execute(request);
-      ObjectNode jsonNode = MyObjectMapper.getMapper().readValue(response.getEntity().getContent(),
-          ObjectNode.class);
-      return new OrganizationEntity.OrganizationEntityBuilder()
-          .setId(jsonNode.get("id").asText())
-          .addProperty("name", jsonNode.get("name"))
-          .addProperty("email", jsonNode.get("email_address"))
-          .addProperty("url", jsonNode.get("links"))
-          .build();
+    try (CloseableHttpClient httpClient = HttpClients.createDefault()) {
+        CloseableHttpResponse response = httpClient.execute(request);
+        ObjectNode jsonNode = MyObjectMapper.getMapper().readValue(response.getEntity().getContent(),
+            ObjectNode.class);
+        return new OrganizationEntity.OrganizationEntityBuilder()
+            .setId(jsonNode.get("id").asText())
+            .addProperty("name", jsonNode.get("name"))
+            .addProperty("email", jsonNode.get("email_address"))
+            .addProperty("url", jsonNode.get("links"))
+            .build();
     } catch (IOException e) {
       e.printStackTrace();
     }

src/main/java/edu/kit/datamanager/ro_crate/writer/ZipWriter.java

@@ -9,7 +9,6 @@
 import edu.kit.datamanager.ro_crate.objectmapper.MyObjectMapper;
 
 import java.io.ByteArrayInputStream;
-import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
 import java.nio.charset.StandardCharsets;
@@ -25,9 +24,25 @@ public class ZipWriter implements WriterStrategy {
 
   @Override
   public void save(Crate crate, String destination) {
-    File file = new File(destination);
-    ZipFile zipFile = new ZipFile(destination);
+    try (ZipFile zipFile = new ZipFile(destination)) {
+      saveMetadataJson(crate, zipFile);
+      saveDataEntities(crate, zipFile);
+    } catch (IOException e) {
+      // can not close ZipFile (threw Exception)
+    }
+  }
+
+  private void saveDataEntities(Crate crate, ZipFile zipFile) {
+    for (DataEntity dataEntity : crate.getAllDataEntities()) {
+      try {
+        dataEntity.saveToZip(zipFile);
+      } catch (ZipException e) {
+        System.out.println("could not save " + dataEntity.getId() + " to zip file!");
+      }
+    }
+  }
 
+  private void saveMetadataJson(Crate crate, ZipFile zipFile) {
     try {
       // write the metadata.json file
       ZipParameters zipParameters = new ZipParameters();
@@ -49,14 +64,5 @@ public void save(Crate crate, String destination) {
     } catch (IOException e) {
       e.printStackTrace();
     }
-
-    // save all the data entities
-    for (DataEntity dataEntity : crate.getAllDataEntities()) {
-      try {
-        dataEntity.saveToZip(zipFile);
-      } catch (ZipException e) {
-        System.out.println("could not save " + dataEntity.getId() + " to zip file!");
-      }
-    }
   }
 }