Java: How to access a private field in a class

gistfile1.java

public static int main(String[] args) {
    try { Private.testFieldAccess(); } 
    catch (Throwable e) { e.printStackTrace(); }
}

private static class Private {
    private String privateString = null;
    
    public Private(String privateString) {
        this.privateString = privateString;
    }
    
    public String getPrivateString() {
        return privateString;
    }
    
    public static final void testFieldAccess() throws Throwable {
        Private privateObject = new Private("The Private Value");
        Field[] fields = Private.class.getDeclaredFields();
        Field privateStringField = Private.class.getDeclaredField("privateString");
        privateStringField.setAccessible(true);
        
        String fieldValue = (String) privateStringField.get(privateObject);
        System.out.println("fieldValue = " + fieldValue);

        String value = privateObject.getPrivateString();
        System.out.println("value: " + value);
    }
}