chore: Avoid comparing potential nulls

dhis-2/dhis-api/src/main/java/org/hisp/dhis/common/QueryOperator.java

@@ -85,7 +85,7 @@ public static QueryOperator fromString(String string) {
     }
 
     // To still support NE operator until it gets removed
-    if (string.trim().equals("NE")) {
+    if ("NE".equals(string.trim())) {
       return NEQ;
     }
 

dhis-2/dhis-api/src/main/java/org/hisp/dhis/datastore/DatastoreQuery.java

@@ -117,11 +117,11 @@ public interface HasPath {
     String getPath();
 
     default boolean isKeyPath() {
-      return getPath().equals("_");
+      return "_".equals(getPath());
     }
 
     default boolean isValuePath() {
-      return getPath().equals(".");
+      return ".".equals(getPath());
     }
   }
 

dhis-2/dhis-api/src/main/java/org/hisp/dhis/interpretation/MentionUtils.java

@@ -68,7 +68,7 @@ public static List<String> removeCustomFilters(List<String> filters) {
     ListIterator<String> filterIterator = filters.listIterator();
     while (filterIterator.hasNext()) {
       String[] filterSplit = filterIterator.next().split(":");
-      if (filterSplit[1].equals("in") && filterSplit[0].equals("mentions")) {
+      if ("in".equals(filterSplit[1]) && "mentions".equals(filterSplit[0])) {
         mentions.add(filterSplit[2]);
         filterIterator.remove();
       }

dhis-2/dhis-api/src/main/java/org/hisp/dhis/scheduling/JobConfiguration.java

@@ -451,6 +451,6 @@ public static Instant maxDelayedExecutionTime(
   private static boolean isUndefinedCronExpression(String cronExpression) {
     return cronExpression == null
         || cronExpression.isEmpty()
-        || cronExpression.equals("* * * * * ?");
+        || "* * * * * ?".equals(cronExpression);
   }
 }

dhis-2/dhis-services/dhis-service-analytics/src/main/java/org/hisp/dhis/analytics/common/ValueTypeMapping.java

@@ -63,7 +63,7 @@ public enum ValueTypeMapping {
       ValueTypeMapping::booleanConverter, ValueTypeMapping::booleanJsonExtractor, Boolean.class);
 
   private static final UnaryOperator<String> BOOLEAN_JSON_EXTRACTOR =
-      value -> value.equalsIgnoreCase("true") ? "1" : "0";
+      value -> "true".equalsIgnoreCase(value) ? "1" : "0";
 
   private final Function<String, Object> converter;
   @Getter private final UnaryOperator<String> selectTransformer;

dhis-2/dhis-services/dhis-service-core/src/main/java/org/hisp/dhis/appmanager/DefaultAppManager.java

@@ -393,7 +393,7 @@ private void installApp(App app) {
 
   @Override
   public boolean isAccessible(App app) {
-    return app.getKey().equals("login")
+    return "login".equals(app.getKey())
         || CurrentUserUtil.hasAnyAuthority(
             List.of(
                 Authorities.ALL.toString(),

dhis-2/dhis-services/dhis-service-core/src/main/java/org/hisp/dhis/dataapproval/hibernate/HibernateDataApprovalStore.java

@@ -755,7 +755,7 @@ public List<DataApprovalStatus> getDataApprovalStatuses(
       final String[] approved = highestApproved == null ? null : highestApproved.split(SQL_CONCAT);
       final int level = approved == null ? 0 : Integer.parseInt(approved[0]) - MAX_APPROVAL_LEVEL;
       final boolean accepted =
-          approved == null ? false : approved[1].substring(0, 1).equalsIgnoreCase("t");
+          approved == null ? false : "t".equalsIgnoreCase(approved[1].substring(0, 1));
       final long approvedOrgUnitId = approved == null ? 0 : Long.parseLong(approved[2]);
 
       // null if not approved

dhis-2/dhis-services/dhis-service-core/src/main/java/org/hisp/dhis/gist/GistPlanner.java

@@ -403,11 +403,11 @@ private static boolean isAllField(String path) {
   }
 
   private boolean isDisplayShortName(String path) {
-    return path.equals("displayShortName") || path.endsWith(".displayShortName");
+    return "displayShortName".equals(path) || path.endsWith(".displayShortName");
   }
 
   private boolean isDisplayNameField(String path) {
-    return path.equals("displayName") || path.endsWith(".displayName");
+    return "displayName".equals(path) || path.endsWith(".displayName");
   }
 
   private static <T> List<T> map1to1(List<T> from, Predicate<T> when, UnaryOperator<T> then) {

dhis-2/dhis-services/dhis-service-core/src/main/java/org/hisp/dhis/query/JpaCriteriaQueryEngine.java

@@ -143,7 +143,7 @@ public List<T> query(Query query) {
             ? CurrentUserUtil.getCurrentUsername()
             : "system-process";
 
-    if (!username.equals("system-process") && shareable && !query.isSkipSharing()) {
+    if (!"system-process".equals(username) && shareable && !query.isSkipSharing()) {
 
       UserDetails userDetails =
           query.getCurrentUserDetails() != null

dhis-2/dhis-services/dhis-service-core/src/main/java/org/hisp/dhis/scheduling/DefaultJobConfigurationService.java

@@ -449,7 +449,7 @@ private static Property getProperty(
             ? jobType.getRelativeApiElements().get(field.getName())
             : "";
 
-    if (relativeApiElements != null && !relativeApiElements.equals("")) {
+    if (relativeApiElements != null && !"".equals(relativeApiElements)) {
       property.setRelativeApiEndpoint(relativeApiElements);
     }
 

dhis-2/dhis-services/dhis-service-core/src/main/java/org/hisp/dhis/security/ImpersonatingUserDetailsChecker.java

@@ -48,7 +48,7 @@ public void check(org.springframework.security.core.userdetails.UserDetails user
 
     boolean userToImpersonateIsSuper =
         userToImpersonate.getAuthorities().stream()
-            .anyMatch(grantedAuthority -> grantedAuthority.getAuthority().equals("ALL"));
+            .anyMatch(grantedAuthority -> "ALL".equals(grantedAuthority.getAuthority()));
 
     if ((!currentUser.isSuper() && userToImpersonateIsSuper)) {
       throw new InsufficientAuthenticationException(

dhis-2/dhis-services/dhis-service-core/src/main/java/org/hisp/dhis/security/oidc/OIDCLoginEnabledCondition.java

@@ -42,7 +42,7 @@ public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata)
       return false;
     }
     String isEnabled = getConfiguration().getProperty(ConfigurationKey.OIDC_OAUTH2_LOGIN_ENABLED);
-    return isEnabled.equalsIgnoreCase("on");
+    return "on".equalsIgnoreCase(isEnabled);
   }
 
   @Override

dhis-2/dhis-services/dhis-service-core/src/main/java/org/hisp/dhis/sms/listener/DataValueSMSListener.java

@@ -333,9 +333,9 @@ private boolean storeDataValue(
           targetValue = Integer.parseInt(targetDataValue.getValue());
         }
 
-        if (operation.equals("+")) {
+        if ("+".equals(operation)) {
           targetValue = targetValue + Integer.parseInt(value);
-        } else if (operation.equals("-")) {
+        } else if ("-".equals(operation)) {
           targetValue = targetValue - Integer.parseInt(value);
         }
 

dhis-2/dhis-services/dhis-service-dxf2/src/main/java/org/hisp/dhis/dxf2/common/Options.java

@@ -51,7 +51,7 @@ public class Options {
   public Options(Map<String, String> options) {
     this.options = options;
     this.assumeTrue =
-        options.get("assumeTrue") == null || options.get("assumeTrue").equalsIgnoreCase("true");
+        options.get("assumeTrue") == null || "true".equalsIgnoreCase(options.get("assumeTrue"));
   }
 
   public Options() {}

dhis-2/dhis-services/dhis-service-dxf2/src/main/java/org/hisp/dhis/dxf2/expressiondimensionitem/ExpressionDimensionItemService.java

@@ -106,7 +106,7 @@ public List<BaseDimensionalItemObject> getExpressionItems(DataDimensionItem data
    * @return true when the expression is valid
    */
   public boolean isValidExpressionItems(String expression) {
-    if (trimToNull(expression) == null || trimToEmpty(expression).equalsIgnoreCase("null")) {
+    if (trimToNull(expression) == null || "null".equalsIgnoreCase(trimToEmpty(expression))) {
       return false;
     }
 

dhis-2/dhis-services/dhis-service-dxf2/src/main/java/org/hisp/dhis/dxf2/pdfform/PdfDataEntryFormUtil.java

@@ -253,9 +253,9 @@ private static String fieldValueFormat(String[] strArrFldName, String fldValue)
       int fieldType = Integer.parseInt(strArrFldName[3].substring(1));
 
       if (fieldType == PdfFieldCell.TYPE_CHECKBOX) {
-        if (fldValue.compareTo("On") == 0) {
+        if ("On".compareTo(fldValue) == 0) {
           fldValue = "true";
-        } else if (fldValue.compareTo("Off") == 0) {
+        } else if ("Off".compareTo(fldValue) == 0) {
           fldValue = null;
         }
       }

dhis-2/dhis-services/dhis-service-field-filtering/src/main/java/org/hisp/dhis/fieldfiltering/FieldFilterParser.java

@@ -87,7 +87,7 @@ private static List<FieldPath> expandField(String field, String prefix) {
           token = fieldSplit[idx];
 
           if ((containsAny(token, ":", "~", "|"))) {
-            if (token.equals(":")) {
+            if (":".equals(token)) {
               idx++;
             }
 
@@ -120,8 +120,8 @@ private static List<FieldPath> expandField(String field, String prefix) {
             transformerParameters.add(transformerNameBuilder.toString());
             break;
           } else if (isFieldSeparator(token)
-              || (token.equals("]") && !insideParameters)
-              || (token.equals("[") && !insideParameters)) {
+              || ("]".equals(token) && !insideParameters)
+              || ("[".equals(token) && !insideParameters)) {
             idx--;
             break;
           }

dhis-2/dhis-services/dhis-service-field-filtering/src/main/java/org/hisp/dhis/fieldfiltering/FieldFilterService.java

@@ -583,7 +583,7 @@ private void applyAccess(
         object,
         fieldPaths,
         isSkipSharing,
-        s -> s.equals("access") || s.endsWith(".access"),
+        s -> "access".equals(s) || s.endsWith(".access"),
         o -> {
           if (o instanceof IdentifiableObject identifiableObject) {
             identifiableObject.setAccess(aclService.getAccess(identifiableObject, userDetails));

dhis-2/dhis-services/dhis-service-node/src/main/java/org/hisp/dhis/fieldfilter/DefaultFieldFilterService.java

@@ -703,7 +703,7 @@ private ComplexNode getProperties(Property currentProperty, Object object, List<
   private boolean isBaseIdentifiableObjectIdOnly(
       @Nonnull Object object, @Nonnull List<String> fields) {
     return fields.size() == 1
-        && fields.get(0).equals("id")
+        && "id".equals(fields.get(0))
         && object instanceof BaseIdentifiableObject;
   }
 

dhis-2/dhis-services/dhis-service-node/src/main/java/org/hisp/dhis/fieldfilter/DefaultFieldParser.java

@@ -54,57 +54,57 @@ public FieldMap parse(String fields) {
 
       // if we reach a field transformer, parse it out here (necessary to
       // allow for () to be used to handle transformer parameters)
-      if ((c.equals(":") && fieldSplit[i + 1].equals(":")) || c.equals("~") || c.equals("|")) {
+      if ((":".equals(c) && ":".equals(fieldSplit[i + 1])) || "~".equals(c) || "|".equals(c)) {
         boolean insideParameters = false;
 
         for (; i < fieldSplit.length; i++) {
           c = fieldSplit[i];
 
-          if (StringUtils.isAlphanumeric(c) || c.equals(":") || c.equals("~") || c.equals("|")) {
+          if (StringUtils.isAlphanumeric(c) || ":".equals(c) || "~".equals(c) || "|".equals(c)) {
             builder.append(c);
-          } else if (c.equals("(")) // start parameter
+          } else if ("(".equals(c)) // start parameter
           {
             insideParameters = true;
             builder.append(c);
-          } else if (insideParameters && c.equals(";")) // allow
+          } else if (insideParameters && ";".equals(c)) // allow
           // parameter
           // separator
           {
             builder.append(c);
-          } else if ((insideParameters && c.equals(")"))) // end
+          } else if ((insideParameters && ")".equals(c))) // end
           {
             builder.append(c);
             break;
-          } else if (c.equals(",") || (c.equals("[") && !insideParameters)) // rewind
+          } else if (",".equals(c) || ("[".equals(c) && !insideParameters)) // rewind
           // and
           // break
           {
             i--;
             break;
           }
         }
-      } else if (c.equals(",")) {
+      } else if (",".equals(c)) {
         putInMap(fieldMap, joinedWithPrefix(builder, prefixList));
         builder = new StringBuilder();
-      } else if (c.equals("[") || c.equals("(")) {
+      } else if ("[".equals(c) || "(".equals(c)) {
         prefixList.add(builder.toString());
         builder = new StringBuilder();
-      } else if (c.equals("]") || c.equals(")")) {
+      } else if ("]".equals(c) || ")".equals(c)) {
         if (!builder.toString().isEmpty()) {
           putInMap(fieldMap, joinedWithPrefix(builder, prefixList));
         }
 
         prefixList.remove(prefixList.size() - 1);
         builder = new StringBuilder();
       } else if (StringUtils.isAlphanumeric(c)
-          || c.equals("*")
-          || c.equals(":")
-          || c.equals(";")
-          || c.equals("~")
-          || c.equals("!")
-          || c.equals("|")
-          || c.equals("{")
-          || c.equals("}")) {
+          || "*".equals(c)
+          || ":".equals(c)
+          || ";".equals(c)
+          || "~".equals(c)
+          || "!".equals(c)
+          || "|".equals(c)
+          || "{".equals(c)
+          || "}".equals(c)) {
         builder.append(c);
       }
     }

dhis-2/dhis-services/dhis-service-node/src/main/java/org/hisp/dhis/fieldfilter/Defaults.java

@@ -41,6 +41,6 @@ public enum Defaults {
   EXCLUDE;
 
   public boolean isExclude() {
-    return this.name().equals("EXCLUDE");
+    return "EXCLUDE".equals(this.name());
   }
 }

dhis-2/dhis-services/dhis-service-tracker/src/main/java/org/hisp/dhis/tracker/imports/preheat/ReferenceTrackerEntity.java

@@ -45,6 +45,6 @@ public class ReferenceTrackerEntity {
   private final String parentUid;
 
   public boolean isRoot() {
-    return this.parentUid.equals("ROOT");
+    return "ROOT".equals(this.parentUid);
   }
 }

dhis-2/dhis-support/dhis-support-db-migration/src/main/java/org/hisp/dhis/db/migration/v33/V2_33_1__Job_configuration_job_type_column_to_varchar.java

@@ -59,7 +59,7 @@ public void migrate(final Context context) throws Exception {
             + "WHERE table_name = 'jobconfiguration' AND column_name = 'jobtype';";
     try (Statement stmt = context.getConnection().createStatement();
         ResultSet rs = stmt.executeQuery(sql); ) {
-      if (rs.next() && rs.getString("data_type").equals("bytea")) {
+      if (rs.next() && "bytea".equals(rs.getString("data_type"))) {
         continueWithMigration = true;
       }
     }

dhis-2/dhis-support/dhis-support-db-migration/src/main/java/org/hisp/dhis/db/migration/v34/V2_34_5__Convert_job_configuration_binary_columns_into_varchar_data_type.java

@@ -71,7 +71,7 @@ private void migrateJobStatusColumn(final Context context) throws Exception {
     boolean continueWithMigration = false;
     try (Statement stmt = context.getConnection().createStatement();
         ResultSet rs = stmt.executeQuery(CHECK_JOB_STATUS_DATA_TYPE_SQL); ) {
-      if (rs.next() && rs.getString("data_type").equals("bytea")) {
+      if (rs.next() && "bytea".equals(rs.getString("data_type"))) {
         continueWithMigration = true;
       }
     }
@@ -142,7 +142,7 @@ private void migrateLastExecutedStatusColumn(final Context context) throws Excep
     boolean continueWithMigration = false;
     try (Statement stmt = context.getConnection().createStatement();
         ResultSet rs = stmt.executeQuery(CHECK_LAST_EXECUTED_STATUS_DATA_TYPE_SQL); ) {
-      if (rs.next() && rs.getString("data_type").equals("bytea")) {
+      if (rs.next() && "bytea".equals(rs.getString("data_type"))) {
         continueWithMigration = true;
       }
     }

dhis-2/dhis-support/dhis-support-db-migration/src/main/java/org/hisp/dhis/db/migration/v34/V2_34_6__Convert_systemsetting_value_column_from_bytea_to_string.java

@@ -83,7 +83,7 @@ public void migrate(final Context context) throws Exception {
       boolean continueWithMigration = false;
       try (Statement stmt = context.getConnection().createStatement();
           ResultSet rs = stmt.executeQuery(CHECK_SYSTEM_SETTING_VALUE_TYPE_SQL); ) {
-        if (rs.next() && rs.getString("data_type").equals("bytea")) {
+        if (rs.next() && "bytea".equals(rs.getString("data_type"))) {
           continueWithMigration = true;
         }
       }

dhis-2/dhis-support/dhis-support-hibernate/src/main/java/org/hisp/dhis/config/DataSourceConfig.java

@@ -178,12 +178,12 @@ private static void executeAfterMethod(MethodExecutionContext executionContext)
       String packageName = className.substring(0, pos);
 
       if (className.contains("org.hisp.dhis.cacheinvalidation.KnownTransactionsService")
-          || methodName.equals("getSingleResult")
-          || methodName.equals("doFilterInternal")) {
+          || "getSingleResult".equals(methodName)
+          || "doFilterInternal".equals(methodName)) {
         break;
       }
 
-      if (packageName.startsWith("org.hisp.dhis") && !methodName.equals("executeAfterMethod")) {
+      if (packageName.startsWith("org.hisp.dhis") && !"executeAfterMethod".equals(methodName)) {
         StackTraceElement nextElement = stackTrace[i - 1];
         String methodName1 = nextElement.getMethodName();
         String className1 = nextElement.getClassName();

dhis-2/dhis-support/dhis-support-hibernate/src/main/java/org/hisp/dhis/config/HibernateConfig.java

@@ -170,7 +170,7 @@ private Properties getAdditionalProperties(DhisConfigurationProvider dhisConfig)
         "hibernate.current_session_context_class",
         "org.springframework.orm.hibernate5.SpringSessionContext");
 
-    if (dhisConfig.getProperty(USE_SECOND_LEVEL_CACHE).equals("true")) {
+    if ("true".equals(dhisConfig.getProperty(USE_SECOND_LEVEL_CACHE))) {
       properties.put(AvailableSettings.USE_SECOND_LEVEL_CACHE, "true");
       properties.put(AvailableSettings.CACHE_REGION_FACTORY, JCacheRegionFactory.class.getName());
       properties.put(AvailableSettings.USE_QUERY_CACHE, dhisConfig.getProperty(USE_QUERY_CACHE));

dhis-2/dhis-support/dhis-support-hibernate/src/test/java/org/hisp/dhis/datasource/StubDriver.java

@@ -50,7 +50,7 @@ public Connection connect(String s, Properties properties) throws SQLException {
 
   @Override
   public boolean acceptsURL(String url) throws SQLException {
-    return url.equals("jdbc:fake:db");
+    return "jdbc:fake:db".equals(url);
   }
 
   @Override

dhis-2/dhis-support/dhis-support-system/src/main/java/org/hisp/dhis/system/util/MathUtils.java

@@ -389,7 +389,7 @@ public static boolean isZero(String value) {
    * @return if the provided string argument is to be considered as a boolean.
    */
   public static boolean isBool(String value) {
-    return value != null && (value.equals("true") || value.equals("false"));
+    return value != null && ("true".equals(value) || "false".equals(value));
   }
 
   /**

dhis-2/dhis-support/dhis-support-test/src/main/java/org/hisp/dhis/http/HttpClientAdapter.java

@@ -207,7 +207,7 @@ default HttpResponse perform(HttpMethod method, String url, RequestComponent...
     List<Header> headers = new ArrayList<>();
     for (RequestComponent c : components) {
       if (c instanceof Header header) {
-        if (header.name().equalsIgnoreCase("ContentType")) {
+        if ("ContentType".equalsIgnoreCase(header.name())) {
           // last provided content type wins
           contentMediaType = header.value().toString();
         } else {
@@ -277,7 +277,7 @@ public boolean success() {
      * @return raw content body in UTF-8 encoding
      */
     public String content(String contentType) {
-      if (contentType.equals("application/json")) {
+      if ("application/json".equals(contentType)) {
         fail("Use one of the other content() methods for JSON");
       }
       String actualContentType = header("Content-Type");

dhis-2/dhis-support/dhis-support-test/src/main/java/org/hisp/dhis/test/utils/Dxf2NamespaceResolver.java

@@ -40,7 +40,7 @@ public String getNamespaceURI(String prefix) {
     if (prefix == null) {
       throw new IllegalArgumentException("No prefix provided!");
     } else {
-      if (prefix.equals("d")) {
+      if ("d".equals(prefix)) {
         return "http://dhis2.org/schema/dxf/2.0";
       } else {
         return XMLConstants.NULL_NS_URI;