Migrated BAEL-7190 to a new module (#16518)

* BAEL-7190 implementation

* Migrated BAEL-7190 to a new module

* Revert "BAEL-7190 implementation"

This reverts commit dd947aefda7b12a0eb06030b5d89f2ada77834a5.

core-java-modules/core-java-security-4/src/test/java/com/baeldung/unrecoverablekeyexception/KeyManagerInitializerUnitTest.java

@@ -0,0 +1,45 @@
+package com.baeldung.unrecoverablekeyexception;
+
+import java.security.UnrecoverableKeyException;
+import org.assertj.core.api.Assertions;
+import org.assertj.core.api.ThrowableAssert.ThrowingCallable;
+import org.junit.Test;
+
+public class KeyManagerInitializerUnitTest {
+
+  @Test
+  public void givenPasswordIsCorrect_whenInitializingTheKeyManager_thenNoExceptionIsThrown() {
+    // Given.
+    String privateKeyPassword = "privateKeyPassword";
+
+    // When.
+    ThrowingCallable initializeKeyManager = () -> KeyManagerInitializer.initializeKeyManager(privateKeyPassword);
+
+    // Then.
+    Assertions.assertThatCode(initializeKeyManager).doesNotThrowAnyException();;
+  }
+
+  @Test
+  public void givenPasswordIsWrong_whenInitializingTheKeyManager_thenUnrecoverableKeyExceptionExceptionIsThrown() {
+    // Given.
+    String privateKeyPassword = "wrongPassword";
+
+    // When.
+    ThrowingCallable initializeKeyManager = () -> KeyManagerInitializer.initializeKeyManager(privateKeyPassword);
+
+    // Then.
+    Assertions.assertThatThrownBy(initializeKeyManager).isInstanceOf(UnrecoverableKeyException.class);
+  }
+
+  @Test
+  public void givenMultipleKeysWithDifferentPasswordsInKeystore_whenInitializingTheKeyManager_thenUnrecoverableKeyExceptionIsThrown() {
+    // Given.
+    String firstPrivateKeyPassword = "abc123";
+
+    // When.
+    ThrowingCallable initializeKeyManager = () -> KeyManagerInitializer.initializeKeyManager(firstPrivateKeyPassword, "multi_entry_keystore.jks");
+
+    // Then.
+    Assertions.assertThatThrownBy(initializeKeyManager).isInstanceOf(UnrecoverableKeyException.class);
+  }
+}