<%#
 Copyright 2013-2017 the original author or authors from the JHipster project.

 This file is part of the JHipster project, see http://www.jhipster.tech/
 for more information.

 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at

      http://www.apache.org/licenses/LICENSE-2.0

 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
-%>
package <%=packageName%>.web.rest.errors;

import org.zalando.problem.AbstractThrowableProblem;
import org.zalando.problem.Status;

import java.net.URI;
import java.util.HashMap;
import java.util.Map;

public class BadRequestAlertException extends AbstractThrowableProblem {

    private String entityName;

    private String errorKey;

    public BadRequestAlertException(String defaultMessage, String entityName, String errorKey) {
        this(ErrorConstants.DEFAULT_TYPE, defaultMessage, entityName, errorKey);
    }

    public BadRequestAlertException(URI type, String defaultMessage, String entityName, String errorKey) {
        super(type, defaultMessage, Status.BAD_REQUEST, null, null, null, getAlertParameters(entityName, errorKey));
        this.entityName = entityName;
        this.errorKey = errorKey;
    }

    public String getEntityName() {
        return entityName;
    }

    public String getErrorKey() {
        return errorKey;
    }

    private static Map<String, Object> getAlertParameters(String entityName, String errorKey) {
        Map<String, Object> parameters = new HashMap<>();
        parameters.put("message", "error." + errorKey);
        parameters.put("params", entityName);
        return parameters;
    }
}

<%#
 Copyright 2013-2017 the original author or authors from the JHipster project.

 This file is part of the JHipster project, see http://www.jhipster.tech/
 for more information.

 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at

      http://www.apache.org/licenses/LICENSE-2.0

 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
-%>
package <%=packageName%>.web.rest.errors;

import org.zalando.problem.AbstractThrowableProblem;
import org.zalando.problem.Status;

import java.net.URI;
import java.util.HashMap;
import java.util.Map;

public class BadRequestAlertException extends AbstractThrowableProblem {

    private final String entityName;

    private final String errorKey;

    public BadRequestAlertException(String defaultMessage, String entityName, String errorKey) {
        this(ErrorConstants.DEFAULT_TYPE, defaultMessage, entityName, errorKey);
    }

    public BadRequestAlertException(URI type, String defaultMessage, String entityName, String errorKey) {
        super(type, defaultMessage, Status.BAD_REQUEST, null, null, null, getAlertParameters(entityName, errorKey));
        this.entityName = entityName;
        this.errorKey = errorKey;
    }

    public String getEntityName() {
        return entityName;
    }

    public String getErrorKey() {
        return errorKey;
    }

    private static Map<String, Object> getAlertParameters(String entityName, String errorKey) {
        Map<String, Object> parameters = new HashMap<>();
        parameters.put("message", "error." + errorKey);
        parameters.put("params", entityName);
        return parameters;
    }
}

Remove Sonar warnings