Remove external Collection utility class for WebAuthn

Closes #10034

common/src/main/java/org/keycloak/common/util/CollectionUtil.java

@@ -55,4 +55,12 @@ public class CollectionUtil {
 
         return true;
     }
+
+    public static boolean isEmpty(Collection<?> collection) {
+        return collection == null || collection.isEmpty();
+    }
+
+    public static boolean isNotEmpty(Collection<?> collection) {
+        return !isEmpty(collection);
+    }
 }

common/src/test/java/org/keycloak/common/util/CollectionUtilTest.java

@@ -4,6 +4,12 @@ import org.junit.Assert;
 import org.junit.Test;
 
 import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+import static org.hamcrest.CoreMatchers.is;
+import static org.hamcrest.MatcherAssert.assertThat;
 
 public class CollectionUtilTest {
 
@@ -39,4 +45,27 @@ public class CollectionUtilTest {
     final String retval = CollectionUtil.join(strings, ",");
     Assert.assertEquals("foo,bar", retval);
   }
+
+  @Test
+  public void testEmptyCollection() {
+    List<String> list = new ArrayList<>();
+
+    assertThat(CollectionUtil.isEmpty(list), is(true));
+    assertThat(CollectionUtil.isNotEmpty(list), is(false));
+
+    list.add("something");
+
+    assertThat(CollectionUtil.isEmpty(list), is(false));
+    assertThat(CollectionUtil.isNotEmpty(list), is(true));
+
+    Set<Object> set = new HashSet<>();
+
+    assertThat(CollectionUtil.isEmpty(set), is(true));
+    assertThat(CollectionUtil.isNotEmpty(set), is(false));
+
+    set.add("something");
+
+    assertThat(CollectionUtil.isEmpty(set), is(false));
+    assertThat(CollectionUtil.isNotEmpty(set), is(true));
+  }
 }

services/src/main/java/org/keycloak/authentication/requiredactions/WebAuthnRegister.java

@@ -31,7 +31,6 @@ import javax.ws.rs.core.Response;
 
 import com.webauthn4j.WebAuthnRegistrationManager;
 import com.webauthn4j.data.AuthenticatorTransport;
-import org.apache.commons.collections4.CollectionUtils;
 import org.jboss.logging.Logger;
 import org.jboss.resteasy.spi.HttpRequest;
 import org.keycloak.WebAuthnConstants;
@@ -40,6 +39,7 @@ import org.keycloak.authentication.InitiatedActionSupport;
 import org.keycloak.authentication.RequiredActionContext;
 import org.keycloak.authentication.RequiredActionProvider;
 import org.keycloak.common.util.Base64Url;
+import org.keycloak.common.util.CollectionUtil;
 import org.keycloak.common.util.UriUtils;
 import org.keycloak.credential.CredentialProvider;
 import org.keycloak.credential.WebAuthnCredentialModelInput;
@@ -327,7 +327,7 @@ public class WebAuthnRegister implements RequiredActionProvider, CredentialRegis
         logger.debugv("aaguid = {0}", attestedCredentialData.getAaguid().toString());
         logger.debugv("attestation format = {0}", attestationStatement.getFormat());
 
-        if (CollectionUtils.isNotEmpty(transports)) {
+        if (CollectionUtil.isNotEmpty(transports)) {
             logger.debugv("transports = [{0}]", transports.stream()
                     .map(AuthenticatorTransport::getValue)
                     .collect(Collectors.joining(",")));

services/src/main/java/org/keycloak/credential/WebAuthnCredentialModelInput.java

@@ -16,7 +16,6 @@
 
 package org.keycloak.credential;
 
-import org.apache.commons.collections4.CollectionUtils;
 import org.keycloak.common.util.Base64;
 
 import com.webauthn4j.data.AuthenticationParameters;
@@ -25,6 +24,7 @@ import com.webauthn4j.data.AuthenticatorTransport;
 import com.webauthn4j.data.attestation.authenticator.AttestedCredentialData;
 import com.webauthn4j.data.attestation.authenticator.COSEKey;
 import com.webauthn4j.data.attestation.statement.AttestationStatement;
+import org.keycloak.common.util.CollectionUtil;
 
 import java.util.Collections;
 import java.util.Set;
@@ -171,7 +171,7 @@ public class WebAuthnCredentialModelInput implements CredentialInput {
               .append(Base64.encodeBytes(authenticationRequest.getCredentialId()))
               .append(",");
         }
-        if (CollectionUtils.isNotEmpty(getTransports())) {
+        if (CollectionUtil.isNotEmpty(getTransports())) {
             final String transportsString = getTransports().stream()
                     .map(AuthenticatorTransport::getValue)
                     .collect(Collectors.joining(","));

services/src/main/java/org/keycloak/forms/login/freemarker/model/WebAuthnAuthenticatorsBean.java

@@ -16,8 +16,8 @@
 package org.keycloak.forms.login.freemarker.model;
 
 import com.webauthn4j.data.AuthenticatorTransport;
-import org.apache.commons.collections4.CollectionUtils;
 import org.keycloak.common.util.Base64Url;
+import org.keycloak.common.util.CollectionUtil;
 import org.keycloak.models.KeycloakSession;
 import org.keycloak.models.RealmModel;
 import org.keycloak.models.UserModel;
@@ -117,7 +117,7 @@ public class WebAuthnAuthenticatorsBean {
              * @return TransportBean
              */
             public static TransportsBean convertFromSet(Set<String> transports) {
-                if (CollectionUtils.isEmpty(transports)) {
+                if (CollectionUtil.isEmpty(transports)) {
                     return new TransportsBean(Transport.UNKNOWN);
                 }