Update the Java version to 8

Author: wikumChamith

api-tests/src/test/java/org/openmrs/module/reporting/calculation/PatientDataCalculationBehaviorTest.java

@@ -12,6 +12,7 @@
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.Map;
 import java.util.Set;
 
@@ -47,8 +48,8 @@ public void setup() throws Exception {
 	public void evaluate_shouldEvaluateAPatientCalculation() throws Exception {
 		Integer patientId1 = 2;
 		Integer patientId2 = 7;
-		Set<PatientIdentifier> identifiers1 = ps.getPatient(patientId1).getIdentifiers();
-		Set<PatientIdentifier> identifiers2 = ps.getPatient(patientId2).getIdentifiers();
+		Set<PatientIdentifier> identifiers1 = new HashSet<>(ps.getPatient(patientId1).getIdentifiers());
+		Set<PatientIdentifier> identifiers2 = new HashSet<>(ps.getPatient(patientId2).getIdentifiers());
 		PatientDataCalculation calculation = new PatientDataCalculationProvider().getCalculation(
 		    "org.openmrs.module.reporting.data.patient.definition.PatientIdentifierDataDefinition", null);
 		Map<String, Object> parameters = new HashMap<String, Object>();

pom.xml

@@ -469,8 +469,8 @@
 					<groupId>org.apache.maven.plugins</groupId>
 					<artifactId>maven-compiler-plugin</artifactId>
 					<configuration>
-						<target>1.6</target>
-						<source>1.6</source>
+						<target>1.8</target>
+						<source>1.8</source>
 					</configuration>
 				</plugin>